Cross-layer link discovery

ABSTRACT

The present disclosure generally discloses a cross-layer link discovery capability configured to support discovery of cross-layer links of a communication network. The cross-layer link discovery capability may be configured to support discovery of cross-layer links between packet network elements and optical network elements of a communication network. The cross-layer link discovery capability may be configured to support automated and reliable discovery of cross-layer links between ports of packet network elements and ports of optical network elements of a communication network. The cross-layer link discovery capability may be configured to support discovery of cross-layer links between ports of packet network elements and ports of optical network elements based on various port matching techniques, such as port classification, port isolation based on port identification, port isolation based on port probing (e.g., active probing, passive probing based on traffic migration, passive probing based on traffic injection, or other port probing types), or the like.

TECHNICAL FIELD

The present disclosure relates generally to communication networks and,more particularly but not exclusively, to discovery of links incommunication networks.

BACKGROUND

Communication networks typically support communications using variouscommunication layers. Many communication networks may supportcommunications at multiple communication layers using cross-layer linksbetween network elements operating at different communication layers.

SUMMARY

The present disclosure generally discloses a cross-layer link discoverycapability configured to support discovery of cross-layer links in acommunication network.

In at least some embodiments, an apparatus is provided. The apparatusincludes a processor and a memory communicatively connected to theprocessor. The processor is configured to identify a set of portsincluding a set of ports of a packet network element and a set of portsof an optical network element, each of the ports having a respectiveconnection associated therewith. The processor is configured to classifythe ports, based on the respective connection types of the ports, todetermine thereby a set of compatible ports, the set of compatible portsincluding at least one of the ports of the packet network element and atleast one of the ports of the optical network element. The processor isconfigured to perform port isolation processing for the set ofcompatible ports, based on the respective connection types of thecompatible ports, to identify a matching port pair including one of theports of the packet network element and one of the ports of the opticalnetwork element that are connected via a cross-layer link. In at leastsome embodiments, a non-transitory computer-readable storage mediumstores instructions which, when executed by a computer, cause thecomputer to perform a corresponding method for supporting discovery ofcross-layer links in a communication network. In at least someembodiments, a corresponding method for supporting discovery ofcross-layer links in a communication network is provided.

In at least some embodiments, an apparatus is provided. The apparatusincludes a processor and a memory communicatively connected to theprocessor. The processor is configured to receive, by a controller, portprobing information associated with a port probing initiated by thecontroller for a first port of a first network element configured forcommunication at a first communication layer. The processor isconfigured to receive, by the controller, port activity informationindicative of port activity at a second port of a second network elementconfigured for communication at a second communication layer differentthan the first communication layer. The processor is configured toidentify, by the controller based on correlation of the port probinginformation and the port activity information, a cross-layer linkconnecting the first port and the second port. In at least someembodiments, a non-transitory computer-readable storage medium storesinstructions which, when executed by a computer, cause the computer toperform a corresponding method for supporting discovery of cross-layerlinks in a communication network. In at least some embodiments, acorresponding method for supporting discovery of cross-layer links in acommunication network is provided.

In at least some embodiments, an apparatus is provided. The apparatusincludes a first network element configured for communication at a firstcommunication layer and including a first port and a second networkelement configured for communication at a second communication layer andincluding a second port, wherein the first port and the second port areconfigured to be connected via a cross-layer link. The first networkelement is configured to receive, from a first element controllerassociated with the first network element, probe information indicativeof probing to be performed on the first port. The first network elementis configured to perform probing on the first port based on the probeinformation indicative of probing to be performed on the first port. Thesecond network element is configured to detect a set of eventsassociated with the second port. The second network element isconfigured to send, toward a second element controller associated withthe second network element, event information indicative of the set ofevents associated with the second port. In at least some embodiments, anon-transitory computer-readable storage medium stores instructionswhich, when executed by a computer, cause the computer to perform acorresponding method for supporting discovery of cross-layer links in acommunication network. In at least some embodiments, a correspondingmethod for supporting discovery of cross-layer links in a communicationnetwork is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings herein can be readily understood by considering thefollowing detailed description in conjunction with the accompanyingdrawings, in which:

FIG. 1 depicts an example communication system configured to supportcross-layer link discovery for discovery of cross-layer links betweenpacket network elements and optical network elements;

FIG. 2 depicts an example process, within the context of a portion ofthe example communication system of FIG. 1, configured to supportdiscovery of cross-layer links at network nodes of a communicationnetwork based on correlation processing and port isolation;

FIG. 3 depicts an example process configured to support discovery ofcross-layer links at network nodes of a communication network using portisolation based on probing;

FIG. 4 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using active probing;

FIG. 5 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 4, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using activeprobing;

FIG. 6 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using passive probingbased on traffic migration probing;

FIG. 7 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 6, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using passiveprobing based on traffic migration probing;

FIG. 8 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using passive probingbased on traffic injection probing;

FIG. 9 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 8, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using passiveprobing based on traffic injection probing;

FIG. 10 depicts an example method for use by a controller to supportdiscovery of cross-layer links based on port classification;

FIG. 11 depicts an example method for use by a controller to supportdiscovery of cross-layer links based on port probing;

FIG. 12 depicts an example method for use by a network element tosupport discovery of cross-layer links at the network element; and

FIG. 13 depicts a high-level block diagram of a computer suitable foruse in performing various functions presented herein.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures.

DETAILED DESCRIPTION

The present disclosure generally discloses a cross-layer link discoverycapability configured to support discovery of cross-layer links of acommunication network. The cross-layer link discovery capability may beconfigured to support discovery of cross-layer links between packetnetwork elements and optical network elements of a communicationnetwork. The cross-layer link discovery capability may be configured tosupport automated and reliable discovery of cross-layer links betweenports of packet network elements and ports of optical network elementsof a communication network. The cross-layer link discovery capabilitymay be configured to support discovery of cross-layer links betweenports of packet network elements and ports of optical network elementsbased on various port matching techniques (e.g., port classification,port isolation based on port identification, port isolation based onport probing, or the like, as well as various combinations thereof). Thecross-layer link discovery capability may be configured to supportautomated (remote) discovery of links interconnecting packet and opticalequipage at one or more network sites in a multi-vendor network. It willbe appreciated that these and various other embodiments and advantagesor potential advantages of the cross-layer link discovery capability maybe further understood by way of reference to the example communicationsystem of FIG. 1.

FIG. 1 depicts an example communication system configured to supportcross-layer link discovery for discovery of cross-layer links betweenpacket network elements and optical network elements.

The communication system 100 includes a multi-layer network (MLN) 110supporting multi-layer communications between network elements operatingat the packet layer and the optical layer, a packet layer controller(PLC) 120, an optical layer controller (OLC) 130, and a networkcontroller (NC) 140.

The MLN 110, as noted above, is configured to support cross-layercommunications between network elements operating at the packet layerand the optical layer (and, accordingly, also may be referred to hereinas a packet-optical (P-O) network).

The MLN 110 includes a set of network nodes (NNs) 111-1-111-5(collectively, NNs 111) configured to support communications within MLN110. The NNs 111 include three cross-layer NNs (illustratively, NNs111-1, 111-2, and 111-5) that are configured to support communicationsat both the packet layer and the optical layer and also includes anumber of optical-only NNs (illustratively, NNs 111-3 and 111-4)configured to support communications at the optical layer). The threecross-layer NNs 111 each include a packet network element (PNE) 112 andan optical network element (ONE) 113 interconnected by a set ofcross-layer links (CLLs) 114 (illustratively, NN 111-1 includes a PNE112-1 and an ONE 113-1 interconnected by a set of CLLs 114-1, NN 111-2includes a PNE 112-2 and an ONE 113-2 interconnected by a set of CLLs114-2, and NN 111-5 includes a PNE 112-5 and an ONE 113-5 interconnectedby a set of CLLs 114-5). The CLLs 114 are communication links betweenports of PNEs 112 and ports of ONEs 113 at NNs 111, respectively(namely, at a given NN 111, a given CLL 114 connects a port of the PNE112 at the given NN 111 and a port of the ONE 113 at the given NN 111).The MLN 110 also includes a set of optical links (OLs) 119 which connectthe NNs 111 at the optical layer (illustratively, supporting variousinterconnections between the ONEs 113 of the three cross-layer NNs 111and the two optical-only NNs 111). The NNs 111 may correspond to networksites (e.g., the NNs 111 may be located at respective network sites(e.g., geographic locations at which the NNs 111 may be deployed). Theports of a PNE 112 and the ports of an ONE 113 at an NN 111 may bereferred to herein as a packet-optical (P-O) port set of the NN 111 orof a site at which the NN 111 is located. It will be appreciated thatthe NNs 111 may be provided by a common vendor or different vendors, thePNEs 112 may be provided by a common vendor or different vendors, theONEs 113 may be provided by a common vendor or different vendors, or thelike. It will be appreciated that, although presented herein as beingpart of an NN 111, the associated PNE 112 and ONE 113 of an NN 111 maybe considered to be separate non-integrated devices (possibly fromdifferent vendors) interconnected using the CLLs 114 therebetween. Itwill be appreciated that, although primarily presented with respect toan arrangement in which the NNs 111 of the MLN 110 correspond torespective network sites, the MLN 110 may include one or more networksites, a network site may include one or more NNs 111, or the like, aswell as various combinations thereof.

The PNEs 112 are packet network elements configured to support packetlayer communications within the MLN 110. The PNEs 112 include variousports, including ports which may be connected to other packet-layerdevices (omitted from FIG. 1 for purposes of clarity) and ports whichmay be connected to ports of respective ONEs 113 via respective CLLs 114as depicted in FIG. 1 (denoted as PNE ports of the PNEs 112, and whichalso may be referred to as ports of the PNE 112 or packet ports of thePNE 112 where the term “packet port” may refer to the port being part ofthe PNE 112 rather than referring to the connection type supported bythe port). The PNEs 112 are configured to support port control functions(e.g., activating and deactivating ports), port monitoring functions(e.g., activity detection on the ports, alarm monitoring and detectionon the ports, or the like), or the like, as well as various combinationsthereof. The PNEs 112 are configured to be communicated with remotelyvia one or more management channels for element management,configuration, control, and information. The PNEs 112 are configured tocommunicate with the PLC 120, based on various control protocols asdiscussed further below, such that the PLC 120 may control the PNEs 112,the PNEs 112 may provide acknowledgments (e.g., acknowledging executionof commands) to the PLC 120, the PNEs 112 may report events (e.g.,alarms, such as loss of signal (LOS), loss of frame (LOF), alarmindication signal (AIS), threshold crossing alert (TCA), or the like) tothe PLC 120, or the like, as well as various combinations thereof. ThePNEs 120 may be configured to communicate with the NC 140 directly orindirectly via the PLC 120 based on various control protocols. Forexample, the PNEs 112 may be routers, switches, or the like.

The ONEs 113 are optical network elements configured to support opticallayer communications within the MLN 110. The ONEs 113 include variousports, including ports which may be connected to ports of respectivePNEs 112 via respective CLLs 114 as depicted in FIG. 1. The ports of theONEs 113 may be denoted as ONE ports of the ONEs 113, and also may bereferred to as ports of the ONE 113 or optical ports of the ONE 113where the term “optical port” may refer to the port being part of theONE 113 rather than referring to the connection type supported by theport. The ONEs 113 also include ONE ports that may be connected to otherONEs 113, e.g. via OLs 119, as depicted in FIG. 1. The ONEs 113 areconfigured to support port control functions (e.g., activating anddeactivating ports), port monitoring functions (e.g., activity detectionon the ports, alarm monitoring and detection on the ports, or the like),or the like, as well as various combinations thereof. The ONEs 113 areconfigured to be communicated with remotely via one or more managementchannels for element management, configuration, control, andinformation. The ONEs 113 are configured to communicate with the OLC130, based on various control protocols as discussed further below, suchthat the OLC 130 may control the ONEs 113, the ONEs 113 may provideacknowledgments (e.g., acknowledging execution of commands) to the OLC130, the ONEs 113 may report events (e.g., alarms, such as alarmsindicative that the received optical signal power is out of range (e.g.,LOS, TCA, or the like) to the OLC 130, or the like, as well as variouscombinations thereof. The ONEs 130 may be configured to communicate withthe NC 140 directly or indirectly via the OLC 130 based on variouscontrol protocols. For example, the ONEs 113 may include reconfigurableoptical add-drop multiplexers (ROADMs), optical switches (OSs), opticalcross-connect (OXC) devices, or the like. It will be appreciated thateach of the ONEs 113 may use electronic switching, optical switching, ora combination of electronic and optical switching. It will beappreciated that, while direct monitoring of ONE ports may not bepossible on OXCs, indirect activity detection techniques may be used.

The CLLs 114 interconnect PNE ports on PNEs 112 and ONE ports on ONEs113 (where a given CLL 114 interconnects a PNE port and an ONE port at asite). The CLLs 114 may be electrical or optical in nature. For example,electrical-based CLLs 114 may be high-speed Ethernet connections or OTNsignals terminated on the PNE 112 (e.g., router or other suitable typeof PNE 112). For example, optical-based CLLs 114 may include any formatof digital signal (Ethernet, OTN, or the like) that is connected to thePNE 112 optically and that remain optical in ONE 113 (i.e., the digitalsignals are not converted from optical to electrical within the opticaldevice before being groomed and transmitting optically to the network).If the signal is converted, then we consider it to be an electricalsignal here since various fields of the digital signal could beaccessed, if needed, to identify the sending ports. For example,optical-based CLLs 114 may include CLLs 114 in which the PNEs 112 (e.g.,routers or switches) are connected to ONEs 113 having an all-opticalswitching fabric (e.g., an optical crossconnect (OXC) ormicro-electromechanical switch (MEMS)). It is noted that the CLLs 114are assumed to occur only between PNEs 112 and ONEs 113 that aregeographically co-located.

It will be appreciated that, although primarily presented with respectto an arrangement in which each network site includes a single NN 111,each network site may include one or more NNs 111 (and, thus, one ormore PNEs 112, one or more ONEs 113, one or more sets of CLs 114, or thelike, as well as various combinations thereof).

It will be appreciated that, although primarily presented with respectto specific configurations of cross-layer NNs 111 or network sites(namely, a 1:1 arrangement in which a given cross-layer NN 111 ornetwork site includes a single PNE 112 and a single ONE 113), one ormore cross-layer NNs 111 or network sites may have a differentarrangement, such as one or more of a 1:N arrangement in which CLLs 114are used to interconnect a single PNE 112 to multiple ONEs 113 at the NN111 or network site, a N:1 arrangement in which CLLs 114 are used tointerconnect multiple PNEs 112 to a single ONE 113, a N:N arrangement inwhich CLLs are used to interconnect multiple PNEs 112 to multiple ONEs113 (e.g., a network site having two routers and two ROADMs, where thereare CLLs 114 between each router and both ROADMs), or variouscombinations thereof.

It will be appreciated that the MLN 110, although primarily presentedwith respect to specific numbers, types, and arrangements of NNs 111(and associated PNEs 112, ONEs 113, and CLLs 114) and OLs 119, may beconfigured to use various other numbers, types, or arrangements of NNs111 (and associated PNEs 112, ONEs 113, and CLLs 114) and OLs 119.

It will be appreciated that the MLN 110 may include various othernumbers, types, or arrangements of sites, elements, or the like, as wellas various combinations thereof.

The MLN 110, as illustrated in FIG. 1, may be controlled based onvarious control elements (illustratively, PLC 120 for the packet layer,OLC 130 for the optical layer, and NC 140 for overall network control).The control elements may include Element Management Systems (EMSs),Network Management Systems (NMSs), or the like. The control elements maybe based on various control capabilities (e.g., operation as EMSs andNMSs, use of the Operations Management System (OMS), or the like, aswell as various combinations thereof). The control elements may beconfigured to support various control protocols for use in controllingelements of MLN 110, such as the Common Management Information Protocol(CMIP), the Simple Network Management Protocol (SNMP), TransactionLanguage One (TL1), Hypertext Transfer Protocol (HTTP), Openflow,NetConf, Common Object Request Broker Architecture (CORBA) GeneralInter-ORB Protocol (GIOP)/Internet Inter-ORB Protocol (HOP), Topologyand Orchestration Specification for Cloud Applications (TOSCA), or thelike, as well as various combinations thereof. The control elements mayinclude or have associated therewith databases (DBs)/managementinformation bases (MIBs) for storing information related to the controlfunctions provided by the control element (e.g., hardware location,hardware configuration details, card characteristics, assigned portidentifiers, or the like, as well as various combinations thereof). Theoperation of PLC 120, OLC 130, and NC 140 is discussed further below.

The PLC 120 is configured to provide control functions at the packetlayer of MLN 110. The PLC 120 is configured to provide control functionsfor the PNEs 112 of MLN 110. For example, the control functions mayinclude provisioning, management, monitoring, or the like, as well asvarious combinations thereof. The PLC 120 may be configured to providecontrol functions for the PNEs 112 under the control of or based oninteraction with the NC 140. The PLC 120 may be configured to providevarious functions for supporting cross-layer link discovery fordiscovery of CLLs 114 of MLN 110. The PLC 120 may be implemented invarious ways (e.g., as an EMS, based on the OMS, or the like, as well asvarious combinations thereof). The PLC 120 has a packet layer DB/MIB 121associated therewith, which may store various types of information forPLC 120 (e.g., information which PLC 120 may use to provide controlfunctions at the packet layer of MLN 110, information determined by PLC120 based on providing control functions at the packet layer of MLN 110,information discovered by the PLC 120 in conjunction with supportingcross-layer link discovery for discovery of CLLs 114 of MLN 110, or thelike, as well as various combinations thereof). The PLC 120 may beconfigured to support various other packet-related control functions forMLN 110.

The OLC 130 is configured to provide control functions at the opticallayer of MLN 110. The OLC 130 is configured to provide control functionsfor the optical elements of MLN 110 (e.g., the optical NNs 111, the ONEs113, and the like). For example, the control functions may includeprovisioning, management, monitoring, or the like, as well as variouscombinations thereof. The OLC 130 may be configured to provide controlfunctions for the optical elements of MLN 110 under the control of orbased on interaction with the NC 140. The OLC 130 may be configured toprovide various functions for supporting cross-layer link discovery fordiscovery of CLLs 114 of MLN 110. The OLC 130 may be implemented invarious ways (e.g., as an EMS, based on the OMS, or the like, as well asvarious combinations thereof). The OLC 130 has an optical layer DB/MIB131 associated therewith, which may store various types of informationfor OLC 130 (e.g., information which OLC 130 may use to provide controlfunctions at the optical layer of MLN 110, information determined by OLC130 based on providing control functions at the optical layer of MLN110, information discovered by the OLC 130 in conjunction withsupporting cross-layer link discovery for discovery of CLLs 114 of MLN110, or the like, as well as various combinations thereof). The OLC 130may be configured to support various other optical-related controlfunctions for MLN 110.

The NC 140 is configured to provide network control functions for theNNs 111 of MLN 110. For example, the network control functions mayinclude provisioning, management, monitoring, or the like, as well asvarious combinations thereof. The NC 140 may be configured to providenetwork control functions for the MLN 110 directly, based on control ofor interaction with other control elements (illustratively, PLC 120 andOLC 130), or the like, as well as various combinations thereof. The NC140 may be configured to provide various functions for supportingcross-layer link discovery for discovery of CLLs 114 of MLN 110(embodiments of which are presented with respect to FIG. 2 and FIG. 3).The NC 140 may be implemented in various ways (e.g., as an NMS, based onthe OMS (e.g., as an OMS application host), as a system or deviceconfigured to interface to separate packet and optical managementsystems, or the like, as well as various combinations thereof). The NC140 has an network DB/MIB 141 associated therewith, which may storevarious types of information for NC 140 (e.g., information which NC 140may use to provide control functions for the MLN 110, informationdetermined by NC 140 based on providing control functions for the MLN110, information discovered by the NC 140 in conjunction with supportingcross-layer link discovery for discovery of CLLs 114 of MLN 110, or thelike, as well as various combinations thereof). The NC 140 may beconfigured to support various other network control functions for MLN110.

The communication system 100 is configured to support a cross-layer linkdiscovery capability that may provide support automated and reliablediscovery of CLLs at network nodes of a communication network(illustratively, discovery of CLLs 114 of certain NNs 111 of MLN 110).The CLLs 114 are links between PNE ports of PNEs 112 and ONE ports ofONEs 113 at NNs 111, respectively. The CLLs 114 may be discovered bydiscovering correlations between the port pairs (PNE port-ONE portpairs) connecting the CLLs 114 (namely, at a given NN 111, a given CLL114 connects a PNE port of the PNE 112 at the given NN 111 and an ONEport of the ONE 113 at the given NN 111 such that discovery of acorrelation or match between the PNE port of the PNE 112 at the given NN111 and the ONE port of the ONE 113 at the given NN 111 providesdiscovery of the given CLL 114 that interconnects those ports).Accordingly, communication system 100 may be configured to supportdiscovery of CLLs 114 of NNs 111 of the MLN 110 based on port matchingtechniques (e.g., port classification, port isolation, or the like, aswell as various combinations thereof), which may be further understoodby way of reference to the example process of FIG. 2.

The communication system 100 is configured to support a cross-layer linkdiscovery capability that is configured to support automated andreliable discovery of CLLs at network nodes of a communication network(illustratively, discovery of CLLs 114 of certain NNs 111 of MLN 110).The CLL discovery process, in at least some embodiments, may beconsidered to be a “divide and conquer” solution in that it provides asystematic reduction of potential connections into increasingly smallercandidate subsets, until the packet-optical connection ambiguities canbe resolved. Leveraging possibly-separated packet and optical layernetwork databases (e.g., MIBs), the CLL discovery process performsanalytics on data about the packet and optical devices at network nodesand, if necessary, selective intelligent probing of the ports, todevelop information for unambiguously identifying packet deviceport/optical device port interconnections. There are two general classesof probing techniques that may be employed: active and passive. Theactive probing techniques may involve making disruptive changes (e.g.,to traffic, transmitted signals, routes, or the like) in ports of one ofthe NEs to generate detectable system or element responses by aninterconnected NE. For example, the power level could be reduced on thenetwork-facing ports of a router to generate optical EMS LOS alerts orTCAs. The passive probing techniques may involve obtaining and analyzingsystem configuration, performance, or other data without interferingwith any services. For example, byte or event/condition counts for portson appropriate sides of a connection, or signal presence indicators canbe used to detect presence or absence of traffic on PNE ports and ONEports. The passive probing techniques may involve traffic migrations orinjections. It is noted that both passive and active probing techniquesmay be used to collect training data for analytics. The operationalstate of the network or devices may impact the manner in which theprobing techniques are employed. For example, forpre-operational/non-operational equipage, active techniques may be usedto guarantee results more quickly and with less effort while passiveprobing techniques may be used as an independent validation to removeambiguities, whereas in operational networks and/or devices there may bea greater reliance on passive techniques in order to minimizedisruptions with active probing techniques potentially being used toresolve ambiguities or improve likelihood of any matching results.

FIG. 2 depicts an example process, within the context of a portion ofthe example communication system of FIG. 1, configured to supportdiscovery of cross-layer links at network nodes of a communicationnetwork based on correlation processing and port isolation. The method200 may be executed by the NC 140 of FIG. 1. It is noted that at leastsome of the functions of method 200, although presented in FIG. 2 asbeing performed serially, may be performed contemporaneously or in adifferent order than as presented in FIG. 2.

At block 201, method 200 begins.

At block 210, equipage co-location correlation is performed. It will beappreciated that, given that a CLL is a link at a given NN between a PNEport of a PNE and an ONE port of an ONE, only those ports located at thesame location are expected to be able to be connected via a given CLL.Here, the location may be considered to be a geographic location, whichmay be measured at any suitable level of granularity (e.g., by sitewhere multiple sites are geographically distributed, by internallocation where equipage is located at multiple locations within abuilding (e.g., by floor, rack, bay, or the like), or the like, as wellas various combinations thereof. The equipage co-location correlationmay be performed based on equipage geo-location information which, asdepicted in FIG. 2, may be include PNE geo-location information for PNEsthat is available from the packet layer DB/MIB 131 for PNE ports and ONEgeo-location information for ONEs that is available from the opticallayer DB/MIB 131 for ONE ports (either or both of which, although notdepicted in FIG. 2, also or alternatively may be available from thenetwork DB/MIB 141). For example, the equipage geo-location informationmay include one or more of physical site facility names, streetaddresses, geographic coordinates, or the like, as well as variouscombinations thereof. The equipage co-location correlation may result inone or more sets of geo-correlated ports (e.g., one set ofgeo-correlated ports for each geographic location at which relevantports are identified). The one or more sets of geo-correlated ports eachmay be further analyzed (serially or in parallel), based on various portmatching techniques, to identify matching port pairs (PNE port-ONE portpairs) determined to be endpoints of respective CLLs (i.e., the blocks220-250 discussed further below, which provide port matching techniquesfor identifying matching port pairs, may be performed for each set ofgeo-correlated ports and, thus, also may be considered to be performedfor each site or location). It is noted that, although primarilypresented with respect to embodiments in which each site is processedindependently of other sites, there may be cases in which sites arecoupled or related in some manner (in which case their interdependencymay be addressed by appropriate ordering of the sites and processing ofthe sites based on that ordering).

In general, the blocks 220-230 discussed further below relate to use ofport classification techniques to identify matching port pairs (P-O portpairs) determined to be endpoints of respective CLLs. From the DBs/MIBs,the possible interconnection ports associated with each piece of siteequipment are obtained, along with attributes associated with the ports,such as port type, unique port identifier, signal protocol, signal rate,assigned wavelength (if any), modulation, polarization, and the like.Based on this information, ports at a site for each layer are groupedinto mutually compatible types, i.e., ports in one layer (e.g., packet)that could be candidates for connection to a given port of the otherlayer (e.g., optical). The compatibility of ports may be based on theconnection types supported by the ports (e.g., electrical versusoptical). For large sites with many ports, an efficient data classifierfor objects with discrete characteristics is suitable, especially sincethe space of port types is limited and well known. This allows forpreconstruction of a classification model which can also accommodatelearning for any new port types. For smaller sites, pair-wise comparisonbetween the set of PNE ports and ONE ports may be sufficient to defineport groups in both layers.

In at least some embodiments, port classification may includeclassification of PNE ports and ONE ports into three types of mutuallycompatible P-O port groups as follows: (I) groups of unit size; (II)groups, of size at least two, of electrical connections (i.e.,electrical-to-electrical (E-E) links between the PNE and the ONE); and(III) groups, of size at least two, of optical connections (E-O or E/O-Olinks between the PNE and the ONE).

A Type I port group includes one PNE port and one ONE port, whichrepresent terminations of a CLL therebetween. The ports can terminateeither electrical or optical connections and have sufficientconfiguration information to uniquely associate them with each other. Asa result, the ports in each such group can be considered as matched andremoved from further consideration after the corresponding cross-layerlink information is saved.

A Type II port group represents PNE ports and ONE ports connectedelectrically in some manner (namely, via E-E links between the PNE andthe ONE. The manner in which the PNE port and ONE ports are connectedcould be determined by digital-only means, since the signal transmittedover the CLL is sent and received in a digital electronic format. Inthis case, the sending device can insert a unique port identifier of thesending port in some field of the digital signal and the receivingdevice can extract that field of the digital signal in order to obtainthe unique port identifier of the sending port and, thus, match thesending port to the receiving port. However, in order to support thistype of capability, the sending and receiving devices will have to agreeon which field(s) of the digital signal are to be used to transport theport identifier information (which may be complicated by the fact thatdifferent signal formats (e.g., Ethernet and Optical Transport Network(OTN) may transport the port identifier information in differentlocations), both the sending and receiving devices will need access tothe electronic signal (which may require the introduction of additionaldigital signal processing (DSP) chips on the receiving device), and soforth. While this type of digital extraction processing could beperformed, this step is optional (as indicated at block 240) since theport isolation process (presented in block 250) may be used to determinethe connections for the Type II port group without having to resort tothe digital extraction processing as discussed above (and, thus,obviating the need for agreement on the field of the digital signal inwhich the port ID is communicated, obviating the need for additional DSPchips in the receiving device port cards, and so forth).

A Type III port group represents PNE ports and ONE ports connectedoptically in some manner without further electrical conversion by theoptical NE. As a result, no port identifier can be stored or extractedon the optical side of the connection and, thus, port isolation based onport probing is applied in order to ascertain which PNE ports areconnected to which ONE ports (and, thus, identify the CLLstherebetween).

At block 220, configuration correlation is performed for a given set ofgeo-correlated ports to attempt to identify matching port pairs (PNEport-ONE port pairs) determined to be endpoints of respective CLLs. Theconfiguration correlation may be performed based on configurationinformation which, as depicted in FIG. 2, may include PNE configurationinformation for PNEs (e.g., racks, shelves, slots, cards, ports, or thelike, as well as various combinations thereof) that is available fromthe packet layer DB/MIB 131 for PNE ports and ONE configurationinformation for ONEs (e.g., racks, shelves, slots, cards, ports, or thelike, as well as various combinations thereof) that is available fromthe optical layer DB/MIB 131 for ONE ports (either or both of which,although not depicted in FIG. 2, also or alternatively may be availablefrom the network DB/MIB 141). The configuration correlation may beperformed based on attribute matching using the configurationinformation (e.g., matching attributes of PNE configuration informationand attributes of the ONE configuration information to identify matchingport pairs determined to be endpoints of respective CLLs). In at leastsome embodiments, at worst, a two-loop search may be performed to matchattributes of the PNE configuration information and attributes of theONE configuration information, such that the processing forconfiguration correlation may be on the order of approximately O(N²). Asillustrated in FIG. 2, any matching port pairs that are identified aresaved (these matching port pairs correspond to endpoints of discoveredCLLs, such that additional processing is not required for discovery ofthose CLLs), whereas any remaining unmatched ports may be passed toblock 230 for further analysis, based on port matching techniques (portclassification and port isolation), to identify matching port pairsdetermined to be endpoints of respective CLLs.

At block 230, compatibility correlation is performed for the remainingunmatched ports of the given set of geo-correlated ports in order togroup the remaining unmatched ports into compatible P-O port subsets.The compatibility correlation may be performed based on compatibilityinformation, which may include various types of information which may beused in order to determine whether a PNE port and an ONE port arecompatible with each other. For example, the compatibility informationmay include signal type, speed, color, or the like, as well as variouscombinations thereof. The compatibility correlation may result in one ormore compatible P-O port subsets (e.g., each of which may include one ormore PNE ports and one more ONE ports which, given the compatibilitybetween them, could be further correlated as being endpoints ofrespective CLLs). The one or more compatible P-O port subsets each maybe further analyzed (serially or in parallel), based on various portisolation techniques, to identify matching port pairs (PNE port-ONE portpairs) determined to be endpoints of respective CLLs. As illustrated inFIG. 2, the one or more compatible P-O port subsets may be passed toblock 240 (optionally, such as when the compatible P-O port subsetincludes only E-E interconnections) and to block 250 (e.g., eachcompatible P-O port subset or those not processed at block 240) forfurther analysis, based on port isolation, to identify matching portpairs determined to be endpoints of respective CLLs.

In general, the blocks 240-250 discussed further below relate to use ofport isolation techniques, including configuration based isolation andisolation based on probing, to identify matching port pairs (P-O portpairs) determined to be endpoints of respective CLLs. The port isolationtechniques may be used to match P-O ports into CLL terminations for anyports in the Type II or Type III port groups. The processing of Type IIport groups may be performed as described in block 240 (based on portidentification) or as described in block 250 (based on port probing).The processing of Type III port groups may be performed as described inblock 250 (based on port probing). The port probing can be active orpassive, which may depend on whether or not it is disruptive to servicesusing the ports. In general, active probing may involve (1) sending aport-specific device management command(s) to a first device (apacket-layer or optical-layer device) that will induce a port-specificdevice management alarm or alert to be generated by a second device (thecorresponding interconnected layer device, either optical or packet),(2) receiving a command acknowledgment message from the first device(s),which results from issuance of the port-specific device managementcommand(s) to the first device, (3) receiving the port-specific devicemanagement alarm or alert to be generated by the second device, and (4)performing correlation processing based on the various messages toidentify matching port pairs (e.g., based on information of the variousmessages, such as port identifiers, timestamps, or the like). Ingeneral, passive probing may involve sending port-specific devicemanagement interrogatives to devices in both layers to retrieve portusage, performance, or state information that can be correlated in timeand reply attributes in order to match ports. It is noted that passiveprobes do not induce a port state change in either layer. It is furthernoted that, provided it is not disruptive to a service, passive probingcan also involve traffic migration or injection in order to createdetectable changes in traffic patterns which may be correlated in orderto identify port matches.

At block 240 (an optional block), port isolation based on PNE portidentification may be performed. The port isolation based on PNE portidentification may be performed for each compatible P-O port subsetincluding E-E CLLs (namely, the Type II port groups discussed above).The port isolation based on PNE port identification for a compatible P-Oport subset including E-E CLLs may be performed by, for each PNE port inthe compatible P-O port subset, instructing the associated ONE that isassociated with the PNE port (i.e., the ONE of the NN on which the PNEof that PNE port is located) to extract a PNE port identifier of the PNEport. The port isolation based on PNE port identification may beperformed using extensions to the Ethernet Link Layer Discovery Protocol(LLDP), extensions to Optical Transport Network (OTN) Optical TransportUnit (OUT)/Optical Data Unit (ODU) fields, or the like, as well asvarious combinations thereof. It will be appreciated that the ports mayneed to be in the “UP” state (e.g. powered and functional) in order toperform port isolation based on PNE port identification. In at leastsome embodiments, at worst, a single-loop search may be performed on theONE ports, for each PNE port, to attempt to identify an ONE portmatching the PNE port, such that the processing for port isolation basedon PNE port identification may be on the order of approximately O(N). Asillustrated in FIG. 2, any matching port pairs that are identified aresaved (these matching port pairs correspond to endpoints of discoveredCLLs, such that additional processing is not required for discovery ofthose CLLs), whereas any remaining unmatched ports may be passed toblock 250 for further analysis, based on port isolation techniques(e.g., active probing, passive probing, or a combination thereof), toidentify matching port pairs determined to be endpoints of respectiveCLLs.

At block 250, port isolation based on probing may be performed for eachcompatible P-O port subset. The port isolation based on probing may beperformed for each compatible P-O port subset including E-O or E/O-OCLLs (namely, Type III port groups). The port isolation based on probingalso may be performed for each compatible P-O port subset including E-ECLLs (namely, the Type II port groups discussed above), such as whereport isolation based on PNE port identification is not performed or doesnot successfully identify each port in a compatible P-O port subsetincluding E-E CLLs. The port isolation based on probing enablesidentification of matching ports corresponding to endpoints ofdiscovered CLLs. The port isolation based on probing may include activeprobing (e.g., at least some embodiments of which are presented withrespect to FIGS. 3, 4, and 5). The port isolation based on probing mayinclude passive probing. The port isolation based on passive probing mayinclude port probing based on traffic migration (e.g., at least someembodiments of which are presented with respect to FIGS. 3, 6, and 7).The port isolation based on passive probing may include port probingbased on traffic injection (e.g., at least some embodiments of which arepresented with respect to FIGS. 3, 8, and 9). The port isolation basedon probing may include various combinations of such probing types.

The port isolation based on probing, as noted above, may include activeprobing. This type of probing may involve issuing a port-specific devicemanagement command to a packet-layer or optical-layer device that willinduce a port-specific device management alarm, alert, advisory,notification, or the like. Such alarms usually are issued when acharacteristic of a port changes, such as its state (e.g., ON, OFF, UP,DOWN, or the like), its power level (e.g., POWER DETECTED, NO POWERDETECTED, or the like), or the like. An example of active probing isillustrated in FIG. 5 for the packet-to-optical direction. The probingfor a site may be initiated from a CLL discovery process applicationresident in or accessible to a controller or management system (e.g., NC140). In order to initiate active probing, a CLL discovery processapplication may select a device and a port for which probing is to beperformed and send associated probing commands to that device via itsassociated management system (e.g., EMS/OMS). These probing commands mayresult in response messages being returned from both the acting andreacting devices after a short time, which may be different for eachdevice. The probing commands and response messages may be communicatedin one of several standard protocols/languages used in thetelecommunications industry for remote management of networking gear andmachine-to-machine communications (e.g., TL1, SNMP, Openflow, NetCONF,HTTP, CORBA GIOP/IIOP, or the like). The communication format to use fora particular device may be determined either directly from the EMS inthe form of device configuration information or, alternatively, bysending an inert (non-operations impacting) command requesting andlearning the message type by classifying the message format. The probingcommands and response messages are typically based on formats thatinclude a timestamp (or, in the case of Openflow, it is included by thedevice and EMS in the XID field) and a device and port identifier of anyevent directly affecting a port, such as a state change, power levelchange, loss of signal, or the like. The port isolation process may beperformed on each group of mutually compatible PNE ports and ONE portsthat resulted from the classification processing. An example flow forthe case of active probing is illustrated in FIG. 4. In at least someembodiments, active probing is applied to each port of a device only asnecessary (e.g., not to the last unmatched pair of active router-ROADMports). The direction of the active probing indicates on which side theactive probing is initiated. If the probing is initiated on the PNE thenthe PNE is the acting device and the ONE is the reacting device(referred to as the “P→O” direction) and, vice versa, if the probe isinitiated on the ONE then the ONE is the acting device and the PNE isthe reacting device (referred to as the “O→P” direction). The probingprocess steps in one direction mirror that of the other direction, soboth directions are covered by the process of FIG. 4 but only onedirection (namely, P→O) is presented in the example of FIG. 5. Beforeprobing begins, any critical services can be optionally migrated toother ports to avoid significant service disruption. In at least someembodiments of active probing, a port is selected, a port modulationpattern is then selected, and the device commands for the pattern arecommunicated by the CLL discovery process application to the PNE via itsEMS. It is noted that generating a unique sequence of command eventsensures that a detected response is attributable to the specific probeand, in at least some embodiments, the uniqueness can be reinforcedusing coding. After some delay, the command sequence in turn inducesresponses from the optical EMS, which should exhibit the same overallpattern as the probe command pattern, although the responses may not beone-for-one. For example, setting a router port state to DOWN couldgenerate periodic LOS alarms on the ROADM until the alarm is cleared bysetting the router port state back to UP. These time-stamped responsemessages are trapped and saved for subsequent analysis. Any servicesmigrated can be optionally reverted to the original port after probingof the port is complete. After one or more ports have been probed andthe corresponding event sequences generated, there are two responsesignals available in each probe time window that may be correlated toidentify matching ports: (1) the pattern of acknowledgements from theactive NE for each probe command sequence (2) and the pattern ofresponses induced on the reactive NE. These time-stamped responses aresuitable for cross-correlation which, once successfully done, yields theidentifier of the port responding to the port state changes (such thatthese two ports may be identified as being correlated in the sense thatthey are connected via a CLL). The cross-correlation of time-stampedinformation (e.g., the pattern of acknowledgements and pattern ofresponses) may be based on convolution or using other suitablecross-correlation techniques. In at least some embodiments, afterprobing of the compatible P-O port subset is completed in one probingdirection, the process optionally may be performed in the other probingdirection (e.g., for verification, if there is ambiguity to resolve, ifnetwork operational state is not a concern, or the like). In activeprobing, binary or non-binary port state modifications may be used. Ingeneral, in binary probes (e.g., port state modifications DOWN or UP),probe patterns include not only serial state changes, but also havefixed (or, optionally, distinctly varied) temporal interspacing of thestate changes (e.g., inter-arrival time series) such that across-correlated response message pattern can be matched in either orboth the state change series or the relative temporal interspacing ofthe state changes. In at least some embodiments, non-binary port statemodifications may be used (e.g., with the push toward energy efficiencyof networking equipment, port power may have more than two discreteadjustable levels and, thus, power level adjustments (higher or lower)combined with TCAs would suffice to generate an active probe responsethat could be cross-correlated without disrupting the service).

The port isolation based on probing, as noted above, may include passiveprobing. This type of probing may be employed to minimize in-servicedisruptions. It is noted that, even if active probing is ultimatelyemployed to resolve ambiguities, use of passive probing first in anin-service network could produce CLL port matches, thereby reducing thenumber of ports requiring active probing. In general, passive probing isbased on detecting similar traffic activity patterns on both sides of aCLL. The manner in which traffic activity is determined on a device maydepend on the device type of the device (e.g., packet versus optical).For the PNE, determining traffic activity may be straightforward,because the traffic is in a digital format and packet devices commonlysupport byte counting of the traffic. For the ONE, determining trafficactivity can be less straightforward, but a variety of techniques areavailable. For example, if the CLL is E-E or E/O-O/E, traffic activityon the ONE can be directly measured as byte counts on the optical side.For example, for all connection types, a small amount of light can besnooped and processed by a separate DSP to measure traffic activity(e.g., counting bytes) on the optical NE. For example, traffic activityon the ONE may be determined by measuring received power level andassociating the measured received power level with some level oftraffic. It is noted that the measurement of the received power level atthe ONE may be performed on the client side of the ONE, because opticalconnections there are usually, at least currently, monochromatic andtypically do not have the more strenuous optical engineeringrequirements encountered on the line side (e.g., tune power levels perwavelength, signal/traffic level maintenance, and the like).

It is noted that, however determined, the traffic activity that does getdetected can be either unforced traffic activity (meaning that thetraffic activity is already present on a port at the beginning of thediscovery process, typically due to a service, and no changes areintentionally made to it, although it may change on its own) or forcedtraffic activity (meaning that the traffic activity present on a port isintentionally changed). The two main techniques which may be used forchanging traffic on a port are traffic migration and traffic injection.

The port isolation based on probing, as noted above, may include passiveprobing based on traffic migration (which also may be referred to hereinas service migration). In general, service migration involvestemporarily moving some or all of the services from one PNE port over toone or more alternative ports on the same PNE. The alternative ports maybe referred to as target ports of a service migration. This typicallyrequires sufficient residual capacity on the target ports to accommodatethe migrated services and, further, the target ports need to be suchthat migrating services to them will allow the services to reach theirdestinations (e.g., be part of the same VLAN, or service forwardingusing a FIB or LFIB). In general, to make this worthwhile, the migratedservices also need to have a suitable size (e.g., data rate orbandwidth) to ensure that moving services will result in trafficactivity changes on the original and target ports on both NEs that aresufficiently detectable for correlation purposes. An example of passiveprobing based on service migration is illustrated in FIG. 7 for thepacket-to-optical direction. The probing for a site may be initiatedfrom a CLL discovery process application resident in or accessible to acontroller or management system (e.g., NC 140). The CLL discoveryprocess application may select a PNE port to probe at a site and mayselect suitable target PNE ports that will result in the migratedservice reaching its destination so that the service is not disrupted.The PNE port to probe at the site may be referred to herein as thesource site, although it is noted that the site may not necessarily bethe source of the service, but, rather, just on its route so that theservice moves from the packet to optical domain at the so-called sourcesite. It is noted that there may be more than one target port; however,for simplicity of exposition, only a single target port is describedhere. The CLL discovery process application also may select a servicemigration pattern. The migration pattern may be a series of migrations,back and forth between the original port and the target port, suitablyspaced in time so that the pattern is detectable. In at least someembodiments, coding can be employed to improve signal reliability aswell as allowing the migration pattern to be uniquely association withthe port being probed. The CLL discovery process application, afterselecting the migration pattern, sends a series of migration commands tothe PNE via its EMS. This results in two types of signals beinggenerated: (1) a series of time-stamped responses from the PNE thatacknowledge execution of the migration commands and (2) a set of timeseries giving the traffic activity for each client port on the ONE,which can be harvested via the optical EMS. These constitute two signalsets that can be correlated with themselves and the original probepattern, which itself is a time-ordered series. If the traffic activitychanges in each ONE port are significant enough, the changes will bedetectable, thereby allowing the signals to be correlated and thecorresponding ONE port to be identified. The cross-correlation oftime-stamped information (e.g., the original probe pattern, the seriesof time-stamped responses from the PNE that acknowledge execution of thetraffic migration commands, and the time-stamped traffic activity forthe ports on the ONE) may be based on convolution or using othersuitable cross-correlation techniques. It is noted that the servicemigration at the source site may also induce traffic activity changes inCLLs at other sites, including transit sites en route to the destinationsite and the destination site, such that CLL-related port trafficactivity at those sites could be harvested in order to provideinformation that can be cross-correlated in order to identify matchingports associated with CLLs at those sites (and, thus, identify the CLLsat those sites). It is further noted that it is possible that theservice traffic migrated at the source site may be multiplexed togetherinto one CLL at the destination site, in which case it is expected thatno traffic activity fluctuations would be detected. However, if distinctcrosslinks are used at the destination site, then detectable trafficvariations could be used to match ports there as well, provided thetraffic fluctuations are sufficiently large relative to the othertraffic traversing those CLLs. (Recall that the traffic migrationpattern may be chosen to make the source site port traffic activitychanges detectable, which may or may not suffice for detectability onthe destination crosslinks.) An example flow for the case of passiveprobing based on traffic migration, in the P→O probing direction, isillustrated in FIG. 6. It will be appreciated that, although primarilydescribed with respect to performing traffic migration probing in theP→O probing direction, in at least some embodiments traffic migrationprobing may be performed in the opposite probing direction (namely,O→P). It is noted that, unlike the active probing process, the processfor passive probing based on traffic migration is not symmetrical in theopposite (O→P) probing direction. In at least some embodiments,initiation of a traffic migration process from the optical side entailsreconfiguring optical drops, which might entail a more significantmulti-site reconfiguration of the optical layer to achieve the correctdrops. This could be disruptive to services and also runs the risk ofintroducing optical power instabilities in the WDM layer. In at leastsome embodiments, in order to avoid this and other complications orpotential complications, the O→P probing direction may be configured tosupport a command option for instructing, via the packet and opticalEMSs, one or more non-source sites (e.g., one or more transit sites orthe destination site) to harvest optical and packet crosslink portactivity data for the duration of the source site migration probing.These data may be used for later correlation attempts and port matchingat these non-source sites. Since the routing of the original andmigrated services are known from the topology and network, all sitesalong the routes that use CLLs represent opportunities for port matchingbased on just the one source site port probe.

The port isolation based on probing, as noted above, may include passiveprobing based on traffic injection. In at least some embodiments,traffic injection involves inserting traffic into the packet data planein a controlled manner with sufficiently distinct temporal features fordetection and correlation with ONE port activity. In particular, PNEport activity bursts can be patterned to produce distinctive features inthe traffic activity time series, so that they can be correlated withONE port activity if sufficient time granularity is available from theONE port. An example of passive probing based on traffic injection isillustrated in FIG. 9 for the packet-to-optical direction. It is similarto traffic migration probing, with a difference being that the probesare customized traffic bursts inserted into the data plane such that theinjected traffic traverses a PNE port at the site of interest. Theprobing for a site may be initiated from a CLL discovery processapplication resident in or accessible to a controller or managementsystem (e.g., NC 140). An example flow for the case of passive probingbased on traffic injection, in the P→O probing direction, is illustratedin FIG. 8. It is noted that one requirement for detectability on bothsides of the CLL is to be able to inject a sufficiently large burst,which means the PNE port needs to have adequate residual capacity to dothis. (If a selected PNE port does not, then services can be temporarilymigrated away from it). It is further noted that CLL discovery can alsobe performed in low traffic periods. In combination with servicemigration, this would likely make finding migration targets ports easierwith lower traffic loads. This can be automated with requests to thenetwork resource management system in an SDN context. The CLL discoveryprocess application, after selecting the injection pattern, sendstraffic to a data plane access device for injection into the data planeor sends a series of injection commands to a device configured tocontrol injection of traffic into the data plane (e.g., a packet EMS).This results in two types of signals being generated: (1) a series oftime-stamped messages indicative that of injection of the traffic (e.g.,messages indicative of traffic being injected or propagated forinjection, responses from the PNE that acknowledge execution of themigration commands, or the like) and (2) a set of time series giving thetraffic activity for each client port on the ONE, which can be harvestedvia the optical EMS. These constitute two signal sets that can becorrelated with themselves and the original probe pattern, which itselfis a time-ordered series. If the traffic activity changes in each ONEport are significant enough, the changes will be detectable, therebyallowing the signals to be correlated and the corresponding ONE port tobe identified. The cross-correlation of time-stamped information (e.g.,the original probe pattern, the series of time-stamped messagesassociated with the traffic injection, and the time-stamped trafficactivity for the ports on the optical NE) may be based on convolution orusing other suitable cross-correlation techniques. It will beappreciated that, although primarily described with respect toperforming traffic injection probing in the P→O probing direction, in atleast some embodiments traffic injection probing may be performed in theopposite probing direction (namely, O→P). In general, initiating in theopposite direction (O→P) requires being able to inject traffic into anoptical device from the optical side and have it egress through theclient side of the ONE and, similar to service migration probing, relieson detecting and correlating a crosslink signal at a destination siteafter it is injected into the data plane at a source site.

In at least some embodiments, in order to improve reliability of thecorrelation process for port isolation based on probing, coding may beused to specify the port actions to be performed for the port probing.For example, in the case of active probing, coding may be employed tohelp specify the serial state change patterns on the port. For example,HAM(8,4), or SECDED Hamming coding with 4 signal bits and 4 parity bits,when sent as 8 OFF-ON signals, is able to detect up to two errors in thetransmitted probe pattern, thus allowing time correlation rejection ofsignals upon error detection and thereby flagging a need for a proberetry on a port. Similarly, for example, in the case of passive probingbased on traffic migration, coding may be employed to help specify thesequence of traffic migration actions (or traffic fluctuations due tomigration). Similarly, for example, in the case of passive probing basedon traffic injection, coding may be employed to help specify thesequence of traffic migration actions (or traffic fluctuations due tomigration). In at least some embodiments, coding may be used to improvethe accuracy in distinguishing between port probings that are performedfor multiple ports of a network element or network site concurrently.For example, this may be done by allowing for a unique association of aport probing pattern with a port that is being probed independent of theprobing technique that is used such that, when seeking correlation ofresponse signals, this uniqueness can be exploited to match ports.

It is noted that various vendor commonalities of the NN vendors may beexploited in order to support probing that enables identification ofmatching ports corresponding to endpoints of discovered CLLs, such asEMS messaging to/from devices and/or to/from NetOS/OMS/NMS over themanagement channels using standard machine-to-machine languages orprotocols (e.g., SNMP, TL1, HTTP, CORBA GIOP/IIOP, Openflow, NetConf,and the like), generation and transmission of time-stamped messages(e.g., alarms, alerts, advisories, acknowledgments, or the like) by NEswhen events (e.g., port state change, LOS, traffic activity changes, orthe like) occur on the NEs, NE port activity monitoring and detectioncapabilities), or the like, as well as various combinations thereof.

As illustrated in FIG. 2, any matching port pairs that are identifiedare saved (these matching port pairs correspond to endpoints ofdiscovered CLLs, such that additional processing is not required fordiscovery of those CLLs), whereas any remaining unmatched ports (thereare not expected to be any) may be stored for further analysis in orderto attempt to identify matching port pairs determined to be endpoints ofrespective CLLs.

It will be appreciated that, as noted above, blocks 220-250 may berepeated, serially or in parallel, for each set of geo-correlated portsidentified at block 210.

At block 299, method 200 ends.

It will be appreciated that the output of the method 200 may be thematching port pairs determined (at blocks 220, 240, and 250) to beendpoints of respective CLLs, such that execution of the method 200provides for discovery of the CLLs.

FIG. 3 depicts an example process configured to support discovery ofcross-layer links at network nodes of a communication network using portisolation based on probing. The method 300 may be used to provide block250 of method 200 of FIG. 2 (e.g., method 300 may be executed for eachexecution of block 250 of method 200 for the compatible P-O portsubsets, respectively). The method 300 may be executed by the NC 140 ofFIG. 1. It is noted that at least some of the functions of method 300,although presented in FIG. 3 as being performed serially, may beperformed contemporaneously or in a different order than as presented inFIG. 3.

At block 301, method 300 begins.

At block 310, a compatible P-O port subset is received. The compatibleP-O port subset includes one or more ports of a packet NE (denotedherein as a PNE) and one or more ports of an optical NE (denoted hereinas an ONE). The compatible P-O port subset may be received based onexecution of method 200 of FIG. 2.

At block 320, a port for which probing is to be performed, a probingtype of the probing to be performed for the port, and a probingdirection for the probing of the port are selected. The port is selectedfrom the compatible P-O port subset. The probing type may be activeprobing or passive probing. It is noted that, for services in apre-operational state, active probing may be used to guarantee results,whereas passive probing may be used to validate those results ifnecessary or desired (although either or both techniques may be used invarious ways). It is noted that, for services in an operational state,passive probing may be used to minimize disruptions, whereas activeprobing may be used to resolve ambiguities in those results or tovalidate those results if necessary or desired (although, again, eitheror both techniques may be used in various ways). The probing directionmay be in a direction from the PNE toward the ONE (denoted as P→O) or ina direction from the ONE toward the PNE (denoted as O→P).

If the probing type is active probing, the method 300 proceeds to block330-A, and blocks 330-A, 340-A, 350-A, and 360-A are executed in orderto perform active probing for identifying port matches in the compatibleP-O port subset. At block 330-A, a service is optionally migrated beforeactive probing is initiated. This may include a determination as towhether or not to migrate the service. The migration of the service maybe initiated by NC 140 based on messaging to one or both of PLC 120 orOLC 130. At block 340-A, active port probing is performed. It is notedthat active port probing may include performing a port change action fora port (e.g., making a change to one or more of a port state of a port,a signal traversing the port, a route associated with the port, or thelike) in order to trigger the generation of a detectable system responsethat can be correlated with the port action performed for the port. Forexample, if active probing is performed in the P→O direction, the stateor power of the PNE port may be changed in order to trigger generationof an optical LOS or TCA that will be reported to the OLC. At block350-A, a port cross-correlation function is performed, based on theactive port probing, to identify port matches (e.g., port change actionsare correlated with responses to the port change actions (e.g.,acknowledgments, alarms, alerts, or the like) in order to identity portmatches). At block 360-A, the service is optionally reverted. This mayinclude a determination as to whether or not to revert the service,which may be based on whether or not that service was previouslymigrated (e.g., if the service was previously migrated then the serviceis reverted). The reversion of the service may be initiated by NC 140based on messaging to one or both of PLC 120 or OLC 130. From block360-A, method 300 proceeds to block 370.

If the probing type is passive probing, the method 300 proceeds to block330-P, and blocks 330-P, 340-P, 350-P, and 360-P are executed in orderto perform passive probing for identifying port matches in thecompatible P-O port subset. At block 330-P, a service is optionallymigrated before passive probing is initiated. This may include adetermination as to whether or not to migrate the service. The migrationof the service may be initiated by the NC 140 based on messaging to oneor both of the PLC 120 or the OLC 130. At block 340-P, passive portprobing is performed. It is noted that passive port probing may includeretrieval and analysis of traffic, system performance data, signals, orthe like, as well as various combinations thereof. The passive portprobing may be based on traffic migration, traffic injection, or thelike. For example, passive probing may include collecting byte counts onboth sides of a connection, identifying traffic patterns, or the like.At block 350-P, a port cross-correlation function is performed, based onthe passive port probing, to identify port matches. At block 360-P, theservice is optionally reverted. This may include a determination as towhether or not to revert the service, which may be based on whether ornot that service was previously migrated (e.g., if the service waspreviously migrated then the service is reverted). The reversion of theservice may be initiated by NC 140 based on messaging to one or both ofPLC 120 or OLC 130. From block 360-P, method 300 proceeds to block 370.

At block 370, a determination is made as to whether or not additionalprobing is to be performed for the compatible P-O port subset (e.g., forthe same port, for other ports not yet probed, for validation ofprevious results or port probing, or the like). If a determination ismade that additional probing is to be performed for the compatible P-Oport subset, method 300 returns to block 320, at which point a port,probing type, and probing direction are selected (any of which may bethe same as or different than the previous pass through method 300). Ifa determination is made that additional probing is not to be performedfor the compatible P-O port subset, method 300 proceeds to block 380.

At block 380, results of the port isolation based on probing are output.The results may be saved, provided to one or more systems, or the like,as well as various combinations thereof. The results of the portisolation based on probing may include matching port pairs that havebeen identified (these matching port pairs correspond to endpoints ofdiscovered CLLs, such that additional processing is not required fordiscovery of the CLLs), identification of CLLs determined based onmatching port pairs, identification of any ports for which matching portpairs were not identified based on the port isolation based on probing,or the like, as well as various combinations thereof.

At block 399, method 300 ends.

It will be appreciated that port isolation based on probing may beperformed in various ways, at least some of which are presented withrespect to FIGS. 4 and 5 (for active probing), FIGS. 6 and 7 (forpassive probing based on traffic migration), and FIGS. 8 and 9 (forpassive probing based on traffic injection).

FIG. 4 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using active probing. Themethod 400 is related to probing at a particular site (which, asdiscussed with respect to block 210 of FIG. 2, may be a location forwhich a compatible P-O port subset has been generated for analysis inidentifying CLLs at the particular site). The method 400 may be executedby the NC 140 of FIG. 1. It is noted that the functions of method 400,although presented in FIG. 4 as being performed serially, may beperformed contemporaneously or in a different order than as presented inFIG. 4.

At block 401, method 400 begins.

At block 405, a compatible P-O port subset is received. The compatibleP-O port subset is associated with site (or location) currently beingevaluated (i.e., active probing is performed at the site for identifyingCLLs at the site). The compatible P-O port subset, as noted above,includes one or more ports of a PNE and one or more ports of an ONE. Thecompatible P-O port subset may be received based on execution of method200 of FIG. 2.

At block 410, a probing direction is selected. The probing direction maybe in a direction from the PNE toward the ONE (denoted as P→O) or in adirection from the ONE toward the PNE (denoted as O→P). The probingdirection that is selected dictates the selection of ports from thecompatible P-O port subset for evaluation and the manner in whichevaluation is performed.

At block 415, a port is selected from the compatible P-O port subset. Ifthe probing direction is P→O, the port that is selected is a PNE port.If the probing direction is O→P, the port that is selected is an ONEport.

At block 420, a determination is made as to whether any ports remain inthe compatible P-O port subset. In a first pass through method 400, itis expected that at least one port will still remain in the compatibleP-O port subset; however, as ports are selected and removed from thecompatible P-O port subset, method 400 reaches a state in which no portsremain in the compatible P-O port subset. If a determination is madethat at least one port still remains in the compatible P-O port subset,method 400 proceeds to block 425. If a determination is made that noports remain in the compatible P-O port subset, method 400 proceeds toblock 455.

At block 425, a service is optionally migrated. This may include adetermination as to whether or not to migrate the service. The migrationof the service may be initiated by the NC 140 based on messaging to oneor both of the PLC 120 or the OLC 130.

At block 430, a port action to be performed for the port is selected.The port action to be performed for the port may be configured totrigger the generation of a detectable system response that can becorrelated with the port action performed for the port. The port actionto be performed for the port may include making a change to one or moreof a port state of the port (e.g., changing the port between UP and DOWNstates), a port power level of the port (e.g., modulating port powerlevel of the port), a signal traversing the port, a route associatedwith the port, or the like, as well as various combinations thereof. Theport action may be based on a port modulation pattern, such as a portstate modulation pattern (e.g., alternately switching between UP andDOWN states with a specific timing), a port power modulation pattern(e.g., alternately decreasing and increasing the port power usingpredetermined power levels, predetermined timing of changed, or thelike, as well as various combinations thereof), or the like. It will beappreciated that the port modulation pattern may include an even numberof port power changes such that, at the end of the port modulationpattern, the port is ultimately in the same state as at the start of theport modulation pattern.

At block 435, the port action for the port is applied. The applicationof the port action for the port may be applied based on initiation ofthe port action by a controller and execution of the port action by theNE on which the port is located (e.g., initiated by the NC 140 based onmessaging to the management system associated with the NE on which theport is located, which in turn controls execution of the port action bythe NE on which the port is located). The port action may be appliedbased on port action control information that is provided to the NE onwhich the port is located (e.g., instructions, port action controlinformation such as a port modulation pattern or the like, or the like,as well as various combinations thereof). Additionally, portinformation, associated with port action for the port selected from thecompatible P-O port subset, is stored for later use in cross-correlationprocessing for the port. The port information may include anyinformation suitable for use in cross-correlation processing (e.g., aport ID of the port, timestamp data related to application of the portaction for the port, or the like, as well as various combinationsthereof). If the probing direction is P→O, the port for which the portaction is applied and for which the port information is saved is a PNEport (e.g., based on messaging with PLC 120, as presented in FIG. 5). Ifthe probing direction is O→P, the port for which the port action isapplied and for which the port information is saved is an ONE port(e.g., based on messaging with OLC 130, which is omitted from FIG. 5 forpurposes of clarity).

At block 440, a waiting time period is applied before trapping responsesgenerated based on the application of the port action for the port. Thewaiting time period may be denoted as Δt. It is noted that the waitingtime period Δt may be different depending on various factors (e.g., theresponse times in the electrical domain and the optical domain may bedifferent and may be accounted for), such as whether the probingdirection is P→O or O→P, the types of CLLs being discovered, or thelike, as well as various combinations thereof.

At block 445, responses are received from a management system. Theresponses are responses triggered as a result of application of the portaction for the port selected from the compatible P-O port subset (e.g.,alarms, alerts, advisories, notifications, or the like). The managementsystem may be an EMS or other suitable type of management system. Theresponses are associated with the port on the other side of thecross-layer link from the port selected from the compatible P-O portsubset (e.g., an ONE port where the selected port is a PNE port inprobing direction P→O or a PNE port where the selected port is an ONEport in probing direction O→P). Additionally, port information,associated with the port for which the responses are received, is storedfor later use in cross-correlation processing. The port information mayinclude any information suitable for use in cross-correlation processing(e.g., a port ID of the port, timestamp data associated with thegeneration of the responses, or the like, as well as variouscombinations thereof). If the probing direction is P→O, the port forwhich the port action is applied is a PNE port and this triggersresponses on the optical side such that the responses that are receivedare responses from the management system associated with the ONE (e.g.,OLC 130 managing the ONE, as presented in FIG. 5) and the portinformation that is saved is ONE port information. If the probingdirection is O→P, the port for which the port action is applied is anONE port and this triggers responses on the packet side such that theresponses that are received are responses from the management systemassociated with the PNE (e.g., PLC 120 managing the PNE, which isomitted from FIG. 5 for purposes of clarity) and the port informationthat is saved is PNE port information.

At block 450, a service is optionally reverted. This may include adetermination as to whether or not to revert the service, which may bebased on whether or not that service was previously migrated (e.g., ifthe service was previously migrated then the service is reverted). Thereversion of the service may be initiated by the NC 140 based onmessaging to one or both of the PLC 120 or the OLC 130. From block 450,method 400 returns to block 415, at which point a next port is selectedfrom the compatible P-O port subset.

At block 455, the port actions (from blocks 430 and 435) are correlatedwith the responses (from block 445) to identify port matches. Thecorrelation of the port actions with the responses is based on the portinformation stored for the port actions (in block 435) and the portinformation stored for the responses (in block 445). If the probingdirection is P→O, PNE port actions applied for the PNE ports (e.g., portstate changes, port power modulation, or the like) are correlated withthe ONE EMS responses (e.g., responses triggered by ONE ports based onthe port actions applied for the PNE ports) to identify PNE-ONE portmatches. If the probing direction is O→P, ONE port actions applied forthe ONE ports (e.g., port state changes, port power modulation, or thelike) are correlated with the PNE EMS responses (responses triggered byPNE ports based on the port actions applied for the ONE ports) toidentify ONE-PNE port matches.

At block 460, the results of the port correlation processing are saved.This may include storing port matches, marking discrepancies (e.g.,ports of the compatible P-O port subset for which matches were not foundor not definitively found), or the like.

At block 499, method 400 ends. It will be appreciated that message andinformation flow associated with execution of method 400 may be furtherunderstood by way of reference to FIG. 5.

It will be appreciated that, although primarily presented herein withrespect to use of one probing direction for performing port isolationusing active probing, in at least some embodiments both evaluationsdirections may be used (serially or contemporaneously) for performingport isolation using active probing.

It will be appreciated that method 400 of FIG. 4 may be adapted toperform various other functions presented herein as being supported bythe network controller (e.g., NC 140 of FIG. 1) to perform portisolation using active probing.

FIG. 5 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 4, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using activeprobing.

As depicted in FIG. 5, the system 500 is similar to the system 100 ofFIG. 1. In the example of FIG. 5, active probing is being performed atNN 111-2, to support discovery of the CLLs 114-2 between the PNE 112-2and the ONE 113-2.

The NC 140 initiates active probing by sending a probe message 511(denoted as PROBE(t), which indicates that the probe message 511 is sentat time t) to the PLC 120, which causes the PLC 120 to send acorresponding probe message 512 (also denoted as PROBE(t)) to the PNE112-2. The probe messages 511 and 512 are directed to a target PNE portof the PNE 112-2 and are configured to cause the PNE 112-2 to perform aport action on the PNE port of the PNE 112-2 in order to trigger adetectable response on an ONE port of the ONE 113-2. The port action maychange or vary one or more characteristics of the PNE port of the PNE112-2 (e.g., modulating port state in a pattern, modulating port powerin a pattern, or the like). An example port control pattern is depictedin FIG. 5. The probe message 512 triggers the PNE 112-2 to execute theindicated port action on the PNE port. The probe message 512 alsotriggers the PNE 112-2 to respond to the PLC 120 with a probe responsemessage 513 (denoted as RESPONSE(t+Δ), which indicates that the proberesponse message 513 was initiated at the PNE 112-2 at time t+Δ). Theprobe response message 513 causes the PLC 120 to send a correspondingprobe response message 514 (also denoted as RESPONSE(t+Δ)) to NC 140.

The NN 111-2 supports the active probing responsive to the initiation ofthe active probing by NC 140. The PNE 112-2 receives the probe message512 from the PLC 120 and executes the port action indicated in the probemessage 512 (e.g., modifying one or more characteristics of the PNEport, such as port state or port power level, in accordance with theport control pattern). The execution of the port action by the PNE 112-2for the PNE port results in activity on the ONE 113-2 (namely, on acorresponding ONE port of the ONE 113-2 to which the PNE port of the PNE112-2 is connected via an CLL 114-2), such that cross-correlationprocessing may be performed at the NC 140 to determine that the PNE portand the ONE port are connected via a CLL 114-2 (and, thus, such that theCLL 114-2 may be identified). The activity on the ONE 113-2 may includegeneration of alarms or other information which may be propagatedupstream by the ONE 113-2 to the OLC 130 and from the OLC 130 to the NC140. For example, switching the PNE port from ON to OFF or reducing thepower level of the PNE port may be detected by the ONE port at the otherend of the CLL 114-2 to which the PNE port is connected and may resultin generation of one or more associated alarms (e.g., LOS, AIS, or thelike). The reporting of the activity on the ONE 113-2, responsive to theport action being applied to the PNE port on the PNE 112-2, is indicatedby the response message 521 sent from the ONE 113-2 to the OLC 130(denoted as RESPONSE(t+Δ′), which indicates that response to the portaction applied at the PNE port is triggered on the ONE 113-2 at somelater time that is Δ′ after the time t at which the active probing wasinitiated by the NC 140), which in turn triggers the response message522 sent from the OLC 130 to the NC 140 (also denoted asRESPONSE(t+Δ′)). The response messages 521 and 522 may each includemultiple messages, alarms, notifications, or the like. The responsemessages 521 and 522 are configured to provide the NC 140 withdetectable response information which may be used by the NC 140 in orderto identify which of the ONE ports of the ONE 113-2 is correlated to thePNE port on which the active probing was performed.

The NC 140 is configured to evaluate the information associated with theport probing action performed for the PNE port of the PNE 112-2 in orderto try to identify one of the ONE ports of the ONE 113-2 that isassociated with the PNE port of the PNE 112-2 via a CLL 114-2 betweenthe PNE port of the PNE 112-2 and the one of the ONE ports of the ONE113-2. The information that is evaluated may include informationassociated with the probe message 511 (e.g., the time at which it wassent, the port action that was performed, the time at which the portaction was scheduled to be applied, or the like), information associatedwith the probe response 514 (e.g., the time at which it was received, anindication of the time at which the port action was performed, or thelike or the like), information associated with the response 522 of theONE 113-2 (e.g., optical domain alarms received from the OLC 130responsive to the port action that was performed in the packet domain),or the like, as well as various combinations thereof. For example, ifthe PNE port is turned OFF and ON twice with the PNE port being kept offfor two seconds the first time and three seconds the second time, alarmswill be generated for the ONE port on the other side of the CLL 114-2 towhich that PNE port is connected, such that a correlation of the timingof the alarms on the ONE port to the timing of the OFF/ON PNE portactions may be used to determine that the PNE port and the ONE port arematching ports connected via an associated CLL 114-2.

It will be appreciated that, although primarily presented with respectto an embodiment in which the active probing is provided in the P→Oprobing direction, similar types of messaging may be used for portmatching and CLL identification when the active probing is performed inthe O→P probing direction.

FIG. 6 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using passive probingbased on traffic migration probing. The method 600 is related tomigration of traffic at a source site (which, as discussed with respectto block 210 of FIG. 2, may be a location for which a compatible P-Oport subset has been generated for analysis in identifying CLLs at thesource site). The method 600 may be executed by the NC 140 of FIG. 1. Itis noted that the functions of method 600, although presented in FIG. 6as being performed serially, may be performed contemporaneously or in adifferent order than as presented in FIG. 6.

At block 601, method 600 begins.

At block 605, a compatible P-O port subset is received. The compatibleP-O port subset is associated with the source site (i.e., trafficmigration probing is performed at the source site for identifying CLLsat the source site). The compatible P-O port subset includes one or moreports of a PNE and one or more ports of an ONE. The compatible P-O portsubset may be received based on execution of method 200 of FIG. 2.

At block 610, a probing direction is selected. The probing direction maybe in a direction from the PNE toward the ONE (denoted as P→O) or in adirection from the ONE toward the PNE (denoted as O→P). Here, it isassumed that the probing direction P→O is selected and, accordingly, theremaining blocks of method 600 are related to embodiments in which theprobing direction is P→O.

At block 615, a PNE port is selected from the compatible P-O portsubset. It will be appreciated that a PNE port is selected, because theprobing direction is P→O.

At block 620, a determination is made as to whether any ports remain inthe compatible P-O port subset. In a first pass through method 600, itis expected that at least one port will still remain in the compatibleP-O port subset; however, as ports are selected and removed from thecompatible P-O port subset, method 600 reaches a state in which no portsremain in the compatible P-O port subset. If a determination is madethat at least one port still remains in the compatible P-O port subset,method 600 proceeds to block 625. If a determination is made that noports remain in the compatible P-O port subset, method 600 proceeds toblock 650.

At block 625, a determination is made as to whether a target port isidentified. A target port is a PNE port, at the PNE of the source site,from which traffic may be migrated to the PNE port selected from thecompatible P-O port subset (namely, traffic is migrated into the PNEport selected from the compatible P-O port subset so as to try toidentify a corresponding ONE port connected to the PNE port selectedfrom the compatible P-O port subset via a CLL). In at least someembodiments, this may require finding a threshold amount of traffic inthe target port that can be migrated to the PNE port selected from thecompatible P-O port subset. It is noted that PNEs often have spareports, which may not have any traffic available for migration to the PNEport selected from the compatible P-O port subset via a CLL. If a targetport is not identified, method 600 returns to block 615 (at which pointa next PNE port is selected). If a target port is identified, method 600proceeds to block 630.

At block 630, a traffic migration pattern is selected. The trafficmigration pattern may be defined as a predetermined set of trafficmigrations having a predetermined timing associated therewith. Thetraffic migration pattern may indicate the traffic to be migrated (e.g.,a quantity of traffic, a number of flows, identification of specificflows or traffic, or the like, as well as various combinations thereof),identification of the source and target PNE ports for the trafficmigration, a timing of the migration of the traffic (e.g., a time atwhich it is to be migrated, a length of time between migration of thetraffic to the target port and reversion back to the source port, or thelike), or the like, as well as various combinations thereof. The trafficmigration pattern is configured to change the detectable trafficactivity on a ONE port by migrating some or all of the traffic on a PNEport. For example, the traffic migration pattern may be: MOVE 50% OFTRAFFIC FROM PNE PORT 1 TO PNE PORT 2, WAIT TWO SECONDS, MOVE THETRAFFIC BACK, WAIT THREE SECONDS, MOVE 60% OF THE TRAFFIC FROM PNE PORT1 TO PNE PORT 2, WAIT FOUR SECONDS, and MOVE THE TRAFFIC BACK.

At block 635, the traffic migration pattern is applied, to migratetraffic from the target port to the PNE port selected from thecompatible P-O port subset, to generate optical traffic activity at theONE of the source site that can be correlated to the migrated traffic.The application of the traffic migration pattern for the PNE port may beapplied based on initiation of the traffic migration by a controller andexecution of the traffic migration by the PNE on which the PNE port islocated (e.g., initiated by the NC 140 based on messaging to themanagement system associated with the PNE on which the PNE port islocated, which in turn controls execution of the traffic migrationpattern by the PNE on which the PNE port is located). The trafficmigration pattern may be applied based on control information that isprovided to the PNE on which the PNE port is located (e.g.,instructions, traffic migration control information such as a trafficmigration pattern or the like, or the like, as well as variouscombinations thereof). Additionally, PNE port information, associatedwith migration of traffic from the target port to the PNE port selectedfrom the compatible P-O port subset, is stored for later use incross-correlation processing for the PNE port. The PNE port informationmay include any information suitable for use in cross-correlationprocessing (e.g., a port ID of the PNE port, timestamp data (e.g., atime at which a migration command is sent, a time at which a migrationacknowledgment is received, or the like), traffic activity informationassociated with traffic migrated to the PNE port (e.g., traffic countinformation, traffic characteristics, or the like), or the like, as wellas various combinations thereof).

At block 640, optical activity information, indicative of opticalactivity associated with the ONE, is received from a management system.The optical activity is triggered as a result of the migration oftraffic from the target port to the PNE port selected from thecompatible P-O port subset. The management system may be an EMS or othersuitable type of management system. The optical activity is associatedwith ONE ports on the other side of the cross-layer link from the PNEport selected from the compatible P-O port subset. Additionally, ONEport information, associated with the ONE ports for which opticalactivity information is received, is stored for later use incross-correlation processing. The ONE port information may include anyinformation suitable for use in cross-correlation processing (e.g., aport ID of the ONE port, timestamp data (e.g., a time at which trafficactivity is detected at the ONE port or the like), traffic activityinformation associated with traffic received at the ONE port (e.g.,traffic count information, traffic characteristics, or the like), or thelike, as well as various combinations thereof).

At block 645, a service is optionally reverted. This may include adetermination as to whether or not to revert the migrated traffic fromthe PNE port selected from the compatible P-O port subset back to thetarget port from which it was migrated. From block 645, method 600returns to block 615, at which point a next PNE port is selected fromthe compatible P-O port subset.

At block 650, the traffic migration actions (from blocks 630 and 635)are correlated with optical activity information (from block 640) toidentify port matches. The correlation of the traffic migration actionswith the optical activity information is based on the PNE portinformation associated with migration of traffic from the target port tothe PNE port selected from the compatible P-O port subset (stored inblock 635) and the ONE port information associated with the ONE portsfor which optical activity information is received (stored in block640). The correlation may be based on traffic counts, trafficcharacteristics, or the like, as well as various combinations thereof.

At block 655, the results of the port correlation processing are saved.This may include storing port matches, marking discrepancies (e.g.,ports of the compatible P-O port subset for which matches were not foundor not definitively found), or the like.

At block 699, method 600 ends. It will be appreciated that message andinformation flow associated with execution of method 600 may be furtherunderstood by way of reference to FIG. 7.

It will be appreciated that, although primarily presented herein withrespect to use of the P→O probing direction for performing portisolation using passive probing based on traffic migration, in at leastsome embodiments the O→P probing direction may be used for performingport isolation using passive probing based on traffic migration.

It will be appreciated that, although primarily presented herein withrespect to use of one probing direction for performing port isolationusing passive probing based on traffic migration (again, the P→O probingdirection), in at least some embodiments both evaluations directions maybe used (serially, contemporaneously, concurrently, or the like) forperforming port isolation using passive probing based on trafficmigration.

It will be appreciated that, when port isolation using passive probingbased on traffic migration is used, the migrated traffic that is used asthe basis for identification of CLLs is expected to travel from a sourcesite at which the traffic migration is performed to a destination site(the intended destination of the migrated traffic), either directly orvia one or more transit sites. The method 600 primarily describescorrelation processing that is performed at the source site (e.g., asthe traffic traverses the CLLs between the PNE and the ONE at the sourcesite); however, in at least some embodiments, that same migrated traffic(and knowledge of its migration at the source site) may be leveraged inorder to support port isolation at one or more other sites (e.g., at thedestination site, at one or more transit sites between the source siteand the destination site, or the like, as well as various combinationsthereof). The NC 140 may have an overall view of the correlationprocessing that is being performed at each of the sites such that itwill know that traffic migrated at a source site can be leveraged forCLL identification at other sites (and, if it can, how it can beleveraged for CLL identification).

In at least some embodiments, for example, traffic migrated at the PNEat the source site (such that P→O correlation processing is used at thesource site) might be used to perform correlation processing at thedestination site as the migrated traffic is propagated from the ONEelement of the destination site back up to the PNE element of thedestination site via the CLLs of the destination site (i.e., O→Pcorrelation processing is used at the destination site). The NC 140 mayoptionally trigger O→P correlation processing at the destination site,based on the migration of traffic at the source site, for use inidentifying port matches (and, thus, CLLs) at the destination site. TheNC 140 may monitor port activity at the ONE and the PNE of thedestination site and save associated ONE port information (e.g., portIDs, traffic activity data, or the like, as well as various combinationsthereof) and PNE port information (e.g., port IDs, traffic activitydata, or the like, as well as various combinations thereof) which may becorrelated for use in identifying port matches (and, thus, CLLs) at thedestination site. It will be appreciated that this could be done for allof the ONE ports in the compatible P-O port subset of the destinationsite or could be done for a subset of the ONE ports in the compatibleP-O port subset of the destination site (e.g., for specific ONE ports,such as where certain ONE port drops are known from the optical topologyinformation).

In at least some embodiments, for example, traffic migrated at the PNEat the source site (such that P→O correlation processing is used at thesource site) might be used to perform correlation processing at atransit site as the migrated traffic is propagated from the ONE elementof the transit site back up to the PNE element of the transit site viathe CLLs of the transit site (i.e., O→P correlation processing may beused at the transit site) and/or as the migrated traffic is propagatedfrom the PNE element of the transit site back down to the ONE element ofthe transit site via the CLLs of the transit site (i.e., P→O correlationprocessing may be used at the transit site). The NC 140 may optionallytrigger O→P correlation processing and/or P→O correlation processing atthe transit site, based on the migration of traffic at the source site,for use in identifying port matches (and, thus, CLLs) at the transitsite. The NC 140 may monitor port activity at the ONE and the PNE of thetransit site and save associated ONE port information (e.g., port IDs,traffic activity data, or the like, as well as various combinationsthereof) and PNE port information (e.g., port IDs, traffic activitydata, or the like, as well as various combinations thereof) which may becorrelated for use in identifying port matches (and, thus, CLLs) at thetransit site. It will be appreciated that this could be done for all ofthe ONE ports in the compatible P-O port subset of the transit site orcould be done for a subset of the ONE ports in the compatible P-O portsubset of the transit site (e.g., for specific ONE ports, such as wherecertain ONE port drops are known from the optical topology information).

The use of the migrated traffic that has been migrated at the sourcesite to perform correlation processing at one or more other sites may beused in place of correlation processing being applied at the one or moreother sites (e.g., applied in the sense that the one or more other sitesare source sites for the correlation processing), in combination withcorrelation processing being applied at the one or more other sites(e.g., to increase the likelihood that the CLLs at the one or more othersites are correctly identified, such as where method 600 is beingseparately executed for one of the other sites based on the compatibleP-O port subset determined for the one of the other sites), or the like.

The leveraging of traffic migrated at a source site (i.e., the site ofthe migration) in order to support identification of CLLs at anothersite (e.g., destination site or transit site) may be further understoodby way of reference to FIG. 7.

It will be appreciated that, although primarily presented with respectto embodiments in which traffic migration is performed at the sourcesite in conjunction with correlation processing being performed at thesource site, in at least some embodiments traffic migration may beinitiated at a source site when correlation processing is not beingperformed at the source site (e.g., the correlation processing is notneeded or all port matches at the source site have already beenidentified) so as to support correlation processing at one or more othersites (e.g., one or more destination sites, one or more transit sites,or the like, as well as various combinations thereof).

It will be appreciated that method 600 of FIG. 6 may be adapted toperform various other functions presented herein as being supported bythe network controller (e.g., NC 140 of FIG. 1) to perform portisolation using active probing.

FIG. 7 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 6, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using passiveprobing based on traffic migration probing.

As depicted in FIG. 7, the system 700 is similar to the system 100 ofFIG. 1. In the example of FIG. 7, passive probing, based on migration oftraffic, is being performed at NN 111-2, to support discovery of theCLLs 114-2 between the PNE 112-2 and the ONE 113-2. The traffic ismigrated between PNE ports at the PNE 112-2 and, accordingly, the NN111-2 is considered to be the migration source site. The traffic that ismigrated is propagated from NN 111-2 to NN 111-1 (and, accordingly, theNN 111-1 is considered to be the migration destination site).

The NC 140 initiates passive probing by sending a probe message 711(denoted as PROBE(t), which indicates that the probe message 711 is sentat time t) to the PLC 120, which causes the PLC 120 to send acorresponding probe message 712 (also denoted as PROBE(t)) to the PNE112-2. The probe messages 711 and 712 are directed to the PNE 112-2 andare configured to cause migration of traffic between PNE ports at thePNE 112-2 in order to trigger a detectable response on an ONE port ofthe ONE 113-2. The traffic migration may be from a PNE port of the PNE112-2 that is being evaluated (from a compatible P-O port subsetassociated with the source migration site) to an available PNE port ofthe PNE 112-2. The probe message 712 triggers the PNE 112-2 to migratethe traffic between the indicated PNE ports. The probe message 712 alsotriggers the PNE 112-2 to respond to the PLC 120 with a probe responsemessage 713 (denoted as RESPONSE(t+Δ), which indicates that the proberesponse message 513 was initiated at the PNE 112-2 at time (t+Δ). Theprobe response message 713 causes the PLC 120 to send a correspondingprobe response message 714 (also denoted as RESPONSE(t+Δ)) to the NC140.

The NN 111-2 supports the passive probing responsive to the initiationof the passive probing by NC 140. The PNE 112-2 receives the probemessage 712 from the PLC 120 and executes the traffic migrationindicated in the probe message 712 (e.g., triggering migration oftraffic from the PNE port of the PNE 112-2 that is being evaluated tothe available PNE port of the PNE 112-2). The execution of the trafficmigration by the PNE 112-2 for the PNE port results in port activity onthe ONE 113-2 (namely, on a corresponding ONE port of the ONE 113-2 towhich the PNE port of the PNE 112-2 is connected via an CLL 114-2), suchthat cross-correlation processing may be performed at the NC 140 todetermine that the PNE port and the ONE port are connected via a CLL114-2 (and, thus, such that the CLL 114-2 may be identified). The portactivity on the ONE 113-2 may include traffic activity on the ONE port(e.g., a decrease in the amount of traffic being handled by the ONE portthat is connected to the PNE port that is being evaluated due to themigration of the traffic from the PNE port that is being evaluated tothe available PNE port). For example, migrating traffic of a flow fromthe PNE port that is being evaluated to the available PNE port mayresult in a reduction in the byte count at the ONE port at the other endof the CLL 114-2 to which the PNE port is connected, which may result ingeneration of one or more associated alarms or events associated withthe ONE port, reporting of new byte count information for the ONE port,or the like, as well as various combinations thereof. The reporting ofthe port activity on the ONE 113-2, responsive to the traffic migrationat the PNE port on the PNE 112-2, is indicated by the response message721 sent from the ONE 113-2 to the OLC 130 (denoted as PORTACTIVITY(t+Δ′), which indicates that response to the traffic migrationperformed at the PNE port is triggered on the ONE 113-2 at some latertime that is Δ′ after the time t at which the passive probing wasinitiated by the NC 140), which in turn triggers the response message722 sent from the OLC 130 to the NC 140 (also denoted as PORTACTIVITY(t+Δ′)). The response messages 721 and 722 may each includemultiple messages, alarms, notifications, traffic counts, or the like.The response messages 721 and 722 are configured to provide the NC 140with detectable response information which may be used by the NC 140 inorder to identify which of the ONE ports of the ONE 113-2 is correlatedto the PNE port on which passive probing was performed.

The NC 140 is configured to evaluate the information associated with theport probing action performed for the PNE port of the PNE 112-2 in orderto try to identify one of the ONE ports of the ONE 113-2 that isassociated with the PNE port of the PNE 112-2 via a CLL 114-2 betweenthe PNE port of the PNE 112-2 and the one of the ONE ports of the ONE113-2. The information that is evaluated may include informationassociated with the probe message 711 (e.g., the time at which it wassent, information that describes the traffic migration that wasperformed, the time at which the traffic migration was scheduled to beperformed, or the like), information associated with the probe response714 (e.g., the time at which it was received, an indication of the timeat which the traffic migration was performed, or the like), informationassociated with the response 722 of the ONE 113-2 (e.g., optical domainalarms or traffic count information that was received from the OLC 130responsive to the traffic migration that was performed in the packetdomain), or the like, as well as various combinations thereof. Forexample, if the flow that is migrated from the PNE port is sending 100kbps, the traffic count that is collected from the ONE port on the otherof the CLL 114-2 to which that PNE port is connected will reflect thereduction of 100 kbps, such that a correlation of the timing of thereduced traffic count on the ONE port to the timing of the trafficmigration at the PNE port may be used to determine that the PNE port andthe ONE port are matching ports connected via an associated CLL 114-2.

It will be appreciated that, although primarily presented with respectto an embodiment in which the passive probing based on traffic migrationis provided in the P→O probing direction, similar types of messaging maybe used for port matching and CLL identification when the passiveprobing based on traffic migration is performed in the O→P probingdirection.

FIG. 8 depicts an example process for use by a network controller tosupport discovery of cross-layer links at network nodes of acommunication network based on port isolation using passive probingbased on traffic injection probing. The method 800 is related toinjection of traffic into the data plane such that it traverses a targetsite (which, as discussed with respect to block 210 of FIG. 2, may be alocation for which a compatible P-O port subset has been generated foranalysis in identifying CLLs at the target site). The method 800 may beexecuted by the NC 140 of FIG. 1. It is noted that the functions ofmethod 800, although presented in FIG. 8 as being performed serially,may be performed contemporaneously or in a different order than aspresented in FIG. 8.

At block 801, method 800 begins.

At block 805, a compatible P-O port subset is received. The compatibleP-O port subset is associated with the target site (i.e., trafficmigration probing is performed at the target site for identifying CLLsat the target site). The target site may be a transit site for theinjected traffic or a destination site for the injected traffic. Thecompatible P-O port subset includes one or more ports of a PNE and oneor more ports of an ONE. The compatible P-O port subset may be receivedbased on execution of method 200 of FIG. 2.

At block 810, a probing direction is selected. The probing direction maybe in a direction from the PNE toward the ONE (denoted as P→O) or in adirection from the ONE toward the PNE (denoted as O→P). Here, it isassumed that the probing direction P→O is selected and, accordingly, theremaining blocks of method 800 are related to embodiments in which theprobing direction is P→O.

At block 815, a PNE port is selected from the compatible P-O portsubset. It will be appreciated that a PNE port is selected, because theprobing direction is P→O.

At block 820, a determination is made as to whether any ports remain inthe compatible P-O port subset. In a first pass through method 800, itis expected that at least one port will still remain in the compatibleP-O port subset; however, as ports are selected and removed from thecompatible P-O port subset, method 800 reaches a state in which no portsremain in the compatible P-O port subset. If a determination is madethat at least one port still remains in the compatible P-O port subset,method 800 proceeds to block 825. If a determination is made that noports remain in the compatible P-O port subset, method 800 proceeds toblock 850.

At block 825, a service is optionally migrated. This may include adetermination as to whether or not to migrate the service. The servicethat is migrated may be a service on the PNE port selected from thecompatible P-O port subset. The service may be migrated in order toprevent a disruption to the service, in order to ensure that the PNEport has a utilization level that is low enough that traffic increaseson the PNE port due to the traffic injection create detectable activitychanges on the ONE ports, or the like, as well as various combinationsthereof. The migration of the service may be initiated by the NC 140based on messaging to one or both of the PLC 120 or the OLC 130.

At block 830, a traffic injection pattern is selected. The trafficinjection pattern may be defined as a predetermined set of trafficinjections having a predetermined timing associated therewith. Thetraffic injection pattern may indicate the traffic to be injected (e.g.,a quantity of traffic, a number of flows, or the like, as well asvarious combinations thereof), identification of the target PNE port forthe traffic injection, a timing of the injection of the traffic (e.g., atime at which it is to be injected, a length of time of the trafficinjection, or the like), or the like, as well as various combinationsthereof. The traffic injection pattern is configured to change thedetectable traffic activity on a ONE port by injecting traffic such thatit traverses a PNE port. The traffic injections of the traffic injectionpattern may have similar or different characteristics associatedtherewith, which may be based on one or more of traffic rate, trafficvolume, traffic signal characteristics, or the like, as well as variouscombinations thereof. For example, a traffic injection pattern may be:INJECT TRAFFIC AT 100 KBPS FOR TWO SECONDS, WAIT 2 SECONDS, and INJECTTRAFFIC AT 200 KBPS FOR ONE SECOND. It will be appreciated that variousother traffic characteristics and timings may be used.

At block 835, the traffic injection pattern is applied, to injecttraffic into the data plane such that the injected traffic egresses thePNE port selected from the compatible P-O port subset (and, thus, suchthat it is routed over a CLL to an ONE port of the ONE at the targetsite), to generate optical traffic activity at the ONE of the targetsite that can be correlated to the injected traffic. The application ofthe traffic injection pattern for the PNE port may be applied based oninitiation of the traffic injection by a controller and execution of thetraffic injection by a data plane access device configured to injecttraffic such that the injected traffic traverses the PNE port (e.g.,initiated by the NC 140 based on messaging to the data plane accessdevice, which in turn controls execution of the traffic injectionpattern such that the injected traffic traverses the PNE port). Thetraffic injection pattern may be applied based on control informationthat is provided to the data plane access device (e.g., instructions,traffic migration control information such as a traffic migrationpattern or the like, or the like, as well as various combinationsthereof). Additionally, PNE port information, associated with injectionof traffic that will traverse the PNE port selected from the compatibleP-O port subset, is stored for later use in cross-correlation processingfor the PNE port. The PNE port information may include any informationsuitable for use in cross-correlation processing (e.g., a port ID of thePNE port, timestamp data (e.g., a time at which an injection command issent, a time at which the traffic injection is scheduled to beperformed, or the like), traffic activity information associated withtraffic injected into the data plane such that it traversed to the PNEport (e.g., traffic count information, traffic characteristics, or thelike), or the like, as well as various combinations thereof).

At block 840, optical activity information, indicative of opticalactivity associated with the ONE, is received from a management system.The optical activity is triggered as a result of the injection oftraffic into the data plane such that the injected traffic egresses thePNE port selected from the compatible P-O port subset and is routed overa CLL to an ONE port of the ONE at the target site. The managementsystem may be an EMS or other suitable type of management system. Theoptical activity is associated with ONE ports at the target site(namely, on the other side of the cross-layer link from the PNE portselected from the compatible P-O port subset). Additionally, ONE portinformation, associated with the ONE ports for which optical activityinformation is received, is stored for later use in cross-correlationprocessing. The ONE port information may include any informationsuitable for use in cross-correlation processing (e.g., a port ID of theONE port, timestamp data (e.g., a time at which traffic activity isdetected at the ONE port or the like), traffic activity informationassociated with traffic received at the ONE port (e.g., traffic countinformation, traffic characteristics, or the like), or the like, as wellas various combinations thereof).

At block 845, a service is optionally reverted. This may include adetermination as to whether or not to revert the migrated service backto the PNE port selected from the compatible P-O port subset. Theservice that is reverted may be a service that was migrated in order toprevent a disruption to the service, a service that was migrated inorder to ensure that the PNE port had a utilization level that is lowenough that traffic increases on the PNE port due to the trafficinjection created detectable activity changes on the ONE ports, or thelike, as well as various combinations thereof. From block 845, method800 returns to block 815, at which point a next PNE port is selectedfrom the compatible P-O port subset.

At block 850, the traffic injection actions (from blocks 830 and 835)are correlated with optical activity information (from block 840) toidentify port matches. The correlation of the traffic injection actionswith the optical activity information is based on the PNE portinformation associated with injection of traffic into the data planesuch that it traverses the PNE port selected from the compatible P-Oport subset (stored in block 835) and the ONE port informationassociated with the ONE ports for which optical activity information isreceived (stored in block 840). The correlation may be based on trafficcounts, traffic characteristics, or the like, as well as variouscombinations thereof.

At block 855, the results of the port correlation processing are saved.This may include storing port matches, marking discrepancies (e.g.,ports of the compatible P-O port subset for which matches were not foundor not definitively found), or the like.

At block 899, method 800 ends. It will be appreciated that message andinformation flow associated with execution of method 800 may be furtherunderstood by way of reference to FIG. 9.

It will be appreciated that, although primarily presented herein withrespect to use of the P→O probing direction for performing portisolation using passive probing based on traffic injection, in at leastsome embodiments the O→P probing direction may be used for performingport isolation using passive probing based on traffic injection.

It will be appreciated that, although primarily presented herein withrespect to use of one probing direction for performing port isolationusing passive probing based on traffic injection (again, the P→O probingdirection), in at least some embodiments both evaluations directions maybe used (serially or contemporaneously) for performing port isolationusing passive probing based on traffic injection.

It will be appreciated that, when port isolation using passive probingbased on traffic injection is used, the injected traffic that is used asthe basis for identification of CLLs is expected to travel from aninjection site at which the traffic injection is performed to adestination site (the intended destination of the injected traffic),either directly or via one or more transit sites. The method 800primarily describes correlation processing that is performed at a singletarget site (e.g., a transit site or a destination site); however, in atleast some embodiments, that same injected traffic (and knowledge of itsinjection at the injection site) may be leveraged in order to supportport isolation at multiple sites (e.g., at multiple transit sites, atone or more transit sites and the destination site, or the like). The NC140 may have an overall view of the correlation processing that is beingperformed at each of the sites such that it will know that trafficinjected at the injection site can be leveraged for CLL identificationat multiple other sites (and, if it can, how it can be leveraged for CLLidentification).

In at least some embodiments, for example, traffic injected such that itegresses the PNE port at the target site where the target site is atransit site (such that P→O correlation processing is used at the targetsite) might be used to perform correlation processing at the destinationsite as the injected traffic is propagated from the ONE element of thedestination site back up to the PNE element of the destination site viathe CLLs of the destination site (i.e., O→P correlation processing isused at the destination site). The NC 140 may optionally trigger O→Pcorrelation processing at the destination site, based on the injectionof traffic such that it egresses the PNE port at the transit site, foruse in identifying port matches (and, thus, CLLs) at the destinationsite. The NC 140 may monitor port activity at the ONE and the PNE of thedestination site and save associated ONE port information (e.g., portIDs, traffic activity data, or the like, as well as various combinationsthereof) and PNE port information (e.g., port IDs, traffic activitydata, or the like, as well as various combinations thereof) which may becorrelated for use in identifying port matches (and, thus, CLLs) at thedestination site. It will be appreciated that this could be done for allof the ONE ports in the compatible P-O port subset of the destinationsite or could be done for a subset of the ONE ports in the compatibleP-O port subset of the destination site (e.g., for specific ONE ports,such as where certain ONE port drops are known from the optical topologyinformation).

In at least some embodiments, for example, traffic injected such that itegresses the PNE port at the target site where the target site is atransit site (such that P→O correlation processing is used at the targetsite) might be used to perform correlation processing at a secondtransit site as the injected traffic is propagated from the ONE elementof the second transit site back up to the PNE element of the secondtransit site via the CLLs of the second transit site (i.e., O→Pcorrelation processing may be used at the second transit site) and/or asthe injected traffic is propagated from the PNE element of the secondtransit site back down to the ONE element of the second transit site viathe CLLs of the second transit site (i.e., P→O correlation processingmay be used at the second transit site). The NC 140 may optionallytrigger O→P correlation processing and/or P→O correlation processing atthe second transit site, based on the injection of traffic into the dataplane, for use in identifying port matches (and, thus, CLLs) at thesecond transit site. The NC 140 may monitor port activity at the ONE andthe PNE of the second transit site and save associated ONE portinformation (e.g., port IDs, traffic activity data, or the like, as wellas various combinations thereof) and PNE port information (e.g., portIDs, traffic activity data, or the like, as well as various combinationsthereof) which may be correlated for use in identifying port matches(and, thus, CLLs) at the second transit site. It will be appreciatedthat this could be done for all of the ONE ports in the compatible P-Oport subset of the second transit site or could be done for a subset ofthe ONE ports in the compatible P-O port subset of the second transitsite (e.g., for specific ONE ports, such as where certain ONE port dropsare known from the optical topology information).

The use of the injected traffic that has been injected into the dataplane to perform correlation processing at one or more other sites maybe used in place of correlation processing being applied at the one ormore other sites (e.g., applied in the sense that the one or more othersites are source sites for the correlation processing), in combinationwith correlation processing being applied at the one or more other sites(e.g., to increase the likelihood that the CLLs at the one or more othersites are correctly identified, such as where method 800 is beingseparately executed for one of the other sites based on the compatibleP-O port subset determined for the one of the other sites), or the like.

The leveraging of traffic injected into the data plane to supportidentification of CLLs at a target site in order to supportidentification of CLLs at another site (e.g., destination site ortransit site) may be further understood by way of reference to FIG. 9.

It will be appreciated that, although primarily presented with respectto embodiments in which traffic injection is performed for a target sitein conjunction with correlation processing being performed at the targetsite, in at least some embodiments traffic injection may be performedfor a target when correlation processing is not being performed at thetarget site (e.g., the correlation processing is not needed or all portmatches at the target site have already been identified) so as tosupport correlation processing at one or more other sites (e.g., one ormore destination sites, one or more transit sites, or the like, as wellas various combinations thereof).

It will be appreciated that method 800 of FIG. 8 may be adapted toperform various other functions presented herein as being supported bythe network controller (e.g., NC 140 of FIG. 1) to perform portisolation using active probing.

FIG. 9 depicts example messaging, within the context of the examplecommunication system of FIG. 1 and associated with the example processof FIG. 8, for supporting discovery of cross-layer links at networknodes of a communication network based on port isolation using passiveprobing based on traffic injection probing.

As depicted in FIG. 9, the system 900 is similar to the system 100 ofFIG. 1. In the example of FIG. 9, passive probing, based on injection oftraffic in the packet layer, is being performed in order to trigger atraffic flow on NN 111-2 to support discovery of the CLLs 114-2 betweenthe PNE 112-2 and the ONE 113-2. The traffic is injected at a packetdata plane access point 901 and flows from the packet data plane accesspoint 901 to the NN 111-1 via the NN 111-2 (and, accordingly, the packetdata plane access point 901 is considered to be the source injectionsite, the NN 111-2 is considered to be the injection transit site, andthe NN 111-1 is considered to be the injection destination site).

The NC 140 initiates passive probing by sending a probe message 911(denoted as PROBE(t), which indicates that the probe message 911 is sentat time t) to the PLC 120, which causes the PLC 120 to send acorresponding probe message 912 (also denoted as PROBE(t)) to the packetdata plane access point 901. The probe messages 911 and 912 are directedto packet data plane access point 901 and are configured to causeinjection of traffic at the packet data plane access point 901, suchthat the injected traffic traverses a target PNE port of the PNE 112-2,in order to trigger a detectable response on an ONE port of the ONE113-2.

The packet data plane access point 901 supports the passive probingresponsive to the initiation of the passive probing by NC 140. Thepacket data plane access point 901 receives the probe message 912 fromthe PLC 120 and executes the traffic injection indicated in the probemessage 912 (e.g., triggering injection of traffic at the packet dataplane access point 901 such that the injected traffic traverses a targetPNE port of the PNE 112-2). The execution of the traffic injection bythe packet data plane access point 901 causes the injected traffic toflow through the target PNE port of the PNE 112-2, which results in portactivity on the ONE 113-2 (namely, on a corresponding ONE port of theONE 113-2 to which the PNE port of the PNE 112-2 is connected via an CLL114-2), such that cross-correlation processing may be performed at theNC 140 to determine that the PNE port and the ONE port are connected viaa CLL 114-2 (and, thus, such that the CLL 114-2 may be identified).

The NN 111-2 supports the passive probing responsive to the initiationof the passive probing by NC 140. The PNE 112-2 receives the injectedtraffic from the packet data plane access point 901 and routes thetraffic from the target PNE port of the PNE 112-2 that is beingevaluated to one of the ONE ports of the ONE 113-2 to which the targetPNE port of the PNE 112-2 is connected by one of the CLLs 114-2. Thisresults in port activity on the ONE 113-2 (namely, on a correspondingONE port of the ONE 113-2 to which the PNE port of the PNE 112-2 isconnected via an CLL 114-2), such that cross-correlation processing maybe performed at the NC 140 to determine that the PNE port and the ONEport are connected via a CLL 114-2 (and, thus, such that the CLL 114-2may be identified). The port activity on the ONE 113-2 may includetraffic activity on the ONE port (e.g., an increase in the amount oftraffic being handled by the ONE port that is connected to the PNE portthat is being evaluated due to the injection of the traffic such that ittraverses the PNE port that is being evaluated). For example, injectionof traffic into the packet data plane such that the injected trafficflows over the target PNE port that is being evaluated may result in anincrease in the byte count at the ONE port at the other end of the CLL114-2 to which the target PNE port is connected, which may result ingeneration of one or more associated alarms or events associated withthe ONE port, reporting of new byte count information for the ONE port,or the like, as well as various combinations thereof. The reporting ofthe port activity on the ONE 113-2, responsive to the traffic injectionat the PNE port on the PNE 112-2, is indicated by the response message921 sent from the ONE 113-2 to the OLC 130 (denoted as PORTACTIVITY(t+Δ′), which indicates that response to the traffic injectionperformed at the PNE port is triggered on the ONE 113-2 at some latertime that is Δ′ after the time t at which the passive probing wasinitiated by the NC 140), which in turn triggers the response message922 sent from the OLC 130 to the NC 140 (also denoted as PORTACTIVITY(t+Δ′)). The response messages 921 and 922 may each includemultiple messages, alarms, notifications, traffic counts, or the like.The response messages 921 and 922 are configured to provide the NC 140with detectable response information which may be used by the NC 140 inorder to identify which of the ONE ports of the ONE 113-2 is correlatedto the PNE port on which passive probing was performed.

The NC 140 is configured to evaluate the information associated with theport probing action performed for the PNE port of the PNE 112-2 in orderto try to identify one of the ONE ports of the ONE 113-2 that isassociated with the PNE port of the PNE 112-2 via a CLL 114-2 betweenthe PNE port of the PNE 112-2 and the one of the ONE ports of the ONE113-2. The information that is evaluated may include informationassociated with the probe message 911 (e.g., the time at which it wassent, information that describes the traffic migration that wasperformed, the time at which the traffic migration was scheduled to beperformed, or the like), information associated with the response 922 ofthe ONE 113-2 (e.g., optical domain alarms or traffic count informationthat was received from the OLC 130 responsive to the traffic migrationthat was performed in the packet domain), or the like, as well asvarious combinations thereof. For example, if the flow that is injectedsuch that it traverses the target PNE port is sending 100 kbps, thetraffic count that is collected from the ONE port on the other of theCLL 114-2 to which that PNE port is connected will reflect the increaseof 100 kbps, such that a correlation of the timing of the increasedtraffic count on the ONE port to the timing of the traffic injectiononto the PNE port may be used to determine that the PNE port and the ONEport are matching ports connected via an associated CLL 114-2.

It will be appreciated that, although primarily presented with respectto an embodiment in which the passive probing based on traffic injectionis provided in the P→O probing direction, similar types of messaging maybe used for port matching and CLL identification when the passiveprobing based on traffic injection is performed in the O→P probingdirection.

It will be appreciated that, although primarily presented with respectto embodiments in which port matching based on probing is performed forCLLs that are E-O optical connections, in at least some embodiments portmatching that is based on probing also may be performed for CLLs thatare E/O-O connections (e.g., where the ONEs may be purely photon systemssuch as OXCs, MEMS, or the like). In at least some embodiments, portmatching that for CLLs that are E/O-O connections may be performed usingservice migration and ONE port switching.

It will be appreciated that, although primarily presented with respectto embodiments in which the port matching processing (and, inparticular, port isolation based on port probing) is performed seriallyon a per-port, per-site basis (e.g., one port is probed at a time at asite), various embodiments may be configured to support parallelprocessing at various levels of granularity (e.g., parallel processingof multiple ports at a site, parallel processing of ports at multiplesites, parallel processing of multiple ports across multiple sites, orthe like). In at least some embodiments, within a site, concurrentprobing of multiple ports can be achieved using coding, which allows fora unique association of a port probing pattern with a port that is beingprobed independent of the probing technique that is used such that, whenseeking correlation of response signals, this uniqueness can beexploited to match ports. The benefit of being able to probe multipleports at a site concurrently is that it is expected to speed up theoverall discovery process. It is noted that a nontrivial constraint tobeing able to concurrently probe ports at the same site is the responsetime of the EMS, since excessive probing (e.g., multiple probes within ashort period of time) may cause the EMS to enter a mode of relaying onlythe most critical messages instead of all of them and such a filteringof EMS messages could compromise the ability to identify correlationbetween ports.

It will be appreciated that various combinations of the above-describedport matching techniques (e.g., classification, probing, or the like)may be used in combination to support port matching for identificationof CLLs.

FIG. 10 depicts an example method for use by a controller to supportdiscovery of cross-layer links based on port classification. At block1001, method 1000 begins. At block 1010, a set of ports, including a setof ports of a packet network element and a set of ports of an opticalnetwork element, is identified. The ports have a respective connectiontypes associated therewith (e.g., each port may support an electricalconnection type or an optical connection type). At block 1020, the portsare classified, based on the respective connection types of the ports,to determine thereby a set of compatible ports. The set of compatibleports includes at least one of the ports of the packet network elementand at least one of the ports of the optical network element. At block1030, port isolation processing is performed for the set of compatibleports, based on the respective connection types of the compatible ports,to identify a matching port pair including one of the ports of thepacket network element and one of the ports of the optical networkelement that are connected via a cross-layer link. It will beappreciated that port isolation processing that is performed for the setof compatible ports may result in identification of multiple matchingport pairs connected via respective cross-layer links. At block 1099,method 1000 ends.

FIG. 11 depicts an example method for use by a controller to supportdiscovery of cross-layer links based on port probing. At block 1101,method 1100 begins. At block 1110, the controller receives port probinginformation associated with a port probing initiated by the controllerfor a first port of a first network element configured for communicationat a first communication layer. At block 1120, the controller receivesport activity information indicative of port activity at a second portof a second network element configured for communication at a secondcommunication layer different than the first communication layer. Atblock 1130, the controller identifies, based on correlation of the portprobing information and the port activity information, a cross-layerlink connecting the first port and the second port. At block 1199,method 1100 ends.

FIG. 12 depicts an example method for use by a network element tosupport discovery of cross-layer links at the network element. Asdiscussed further below, the functions of method 1200 may be performedby a network node, which may include a first network element configuredfor communication at a first communication layer and including a firstport (e.g., one of a packet network element or an optical networkelement) and a second network element configured for communication at asecond communication layer and including a second port (e.g., the otherof the packet network element and the optical network element) wherefirst port and the second port are configured to be connected via across-layer link, and a portion of the functions of method 1200 may beperformed by the first network element and a portion of the functions ofmethod 1200 may be performed by the second network element to supportdiscovery of an association of the first port and the second port (and,thus, support identification of the cross-layer link). At block 1201,method 1200 begins. At block 1210, the first network element receives,from a first element controller associated with the first networkelement, probe information indicative of probing to be performed on thefirst port. At block 1220, the first network element performs probing onthe first port based on the probe information indicative of probing tobe performed on the first port. At block 1230, the second networkelement detects a set of events associated with the second port. Atblock 1240, the second network element sends, toward a second elementcontroller associated with the second network element, event informationindicative of the set of events associated with the second port. Atblock 1299, method 1200 ends (although it will be appreciated that thefirst and second network elements may continue to operate to performfunctions that support discovery of cross-layer links therebetween.

It will be appreciated that various embodiments of the cross-layer linkdiscovery capability may provide various advantages or potentialadvantages. For example, various embodiments of the cross-layer linkdiscovery capability may enable automated (remote) discovery of linksinterconnecting IP and optical equipage at one or more network sites ina multi-vendor network, thereby obviating the need for expensive andtime-consuming on-site visits by network personnel (either duringnetwork rollout or turn-up or in subsequent site visits), avoiding humanerrors associated with on-site visits by network personnel to determineand document equipage interconnectivity (both of which are typicallyvulnerable to documentation and observation errors or un-documentednetwork repairs and patches), enabling use of knowledge of theinterconnections for cross-layer (logical and physical layer) networkresource optimization and dynamic management, such as in SDN networking,so that network operators can get the most out of their networkcapacity, and the like. For example, various embodiments of thecross-layer link discovery capability may enable automated (remote)discovery of links interconnecting IP and optical equipage at one ormore network sites in a multi-vendor network using an approach that isvendor independent (i.e., that does not depend strongly on any specificvendor equipage capabilities and features). For example, variousembodiments of the cross-layer link discovery capability may enableautomated (remote) discovery of links interconnecting IP and opticalequipage at one or more network sites in a multi-vendor network whereproprietary features for cross-layer link determination in same-vendordevices cannot be universally applied throughout the network forcross-layer link discovery. For example, various embodiments of thecross-layer link discovery capability may enable automated (remote)discovery of links interconnecting IP and optical equipage for bothpre-operational scenarios and operational scenarios (e.g., the twooperational modes, pre-operational and operational, allow fastinterconnection link determination in non-operating networks while doingso with minimal disruption to active online services in operationalnetworks). For example, various embodiments of the cross-layer linkdiscovery capability may enable automated (remote) discovery of linksinterconnecting IP and optical equipage without requiringstandardization for handling of electrical CLLs, such as withoutrequiring standardization of identification of sending ports in thedigital signal format (e.g., which OUT frame fields to populate),standardization of changes to existing link-layer protocols (e.g., LLDPor the like), or the like. For example, various embodiments of thecross-layer link discovery capability may enable automated (remote)discovery of links interconnecting IP and optical equipage for opticalCLLs (which still may not be possible even where standardizationdiscussed above was realized). It will be appreciated that variousembodiments of the cross-layer link discovery capability may providevarious other advantages or potential advantages.

FIG. 13 depicts a high-level block diagram of a computer suitable foruse in performing various functions described herein.

The computer 1300 includes a processor 1302 (e.g., a central processingunit (CPU), a processor having a set of processor cores, or the like)and a memory 1304 (e.g., a random access memory (RAM), a read onlymemory (ROM), or the like). The processor 1302 and the memory 1304 arecommunicatively connected.

The computer 1300 also may include a cooperating element 1305. Thecooperating element 1305 may be a hardware device. The cooperatingelement 1305 may be a process that can be loaded into the memory 1304and executed by the processor 1302 to implement functions as discussedherein. The cooperating element 1305, when implemented as a process, canbe stored (along with associated data) on a non-transitorycomputer-readable storage medium such as a storage device or otherstorage element (e.g., a magnetic drive, an optical drive, or the like).

The computer 1300 also may include one or more input/output devices1306. The input/output devices 1306 may include one or more of a userinput device (e.g., a keyboard, a keypad, a mouse, a microphone, acamera, or the like), a user output device (e.g., a display, a speaker,or the like), one or more network communication devices or elements(e.g., an input port, an output port, a receiver, a transmitter, atransceiver, or the like), one or more storage devices (e.g., a tapedrive, a floppy drive, a hard disk drive, a compact disk drive, or thelike), or the like, as well as various combinations thereof.

It will be appreciated that computer 1300 of FIG. 13 may represent ageneral architecture and functionality suitable for implementingfunctional elements described herein, portions of functional elementsdescribed herein, or the like, as well as various combinations thereof.For example, computer 1300 may provide a general architecture andfunctionality that is suitable for implementing one or more of an NN111, a PNE 112, an ONE 113, a PLC 120, an OLC 130, an NC 140, or otherelements, devices, functions, or capabilities presented herein.

It will be appreciated that the functions depicted and described hereinmay be implemented in software (e.g., via implementation of software onone or more processors, for executing on a general purpose computer(e.g., via execution by one or more processors) so as to provide aspecial purpose computer, and the like) and/or may be implemented inhardware (e.g., using a general purpose computer, one or moreapplication specific integrated circuits (ASIC), and/or any otherhardware equivalents).

It will be appreciated that at least some of the functions discussedherein as software methods may be implemented within hardware, forexample, as circuitry that cooperates with the processor to performvarious functions. Portions of the functions/elements described hereinmay be implemented as a computer program product wherein computerinstructions, when processed by a computer, adapt the operation of thecomputer such that the methods and/or techniques described herein areinvoked or otherwise provided. Instructions for invoking the variousmethods may be stored in fixed or removable media (e.g., non-transitorycomputer-readable media), transmitted via a data stream in a broadcastor other signal bearing medium, and/or stored within a memory within acomputing device operating according to the instructions.

It will be appreciated that the term “or” as used herein refers to anon-exclusive “or” unless otherwise indicated (e.g., use of “or else” or“or in the alternative”).

It will be appreciated that, although various embodiments whichincorporate the teachings presented herein have been shown and describedin detail herein, those skilled in the art can readily devise many othervaried embodiments that still incorporate these teachings.

What is claimed is:
 1. An apparatus, comprising: a controller, thecontroller comprising a processor and a memory communicatively connectedto the processor, the processor configured to: receive port probinginformation associated with a port probing initiated for a first port ofa first network element configured for communication at a firstcommunication layer; receive port activity information indicative ofport activity at a second port of a second network element configuredfor communication at a second communication layer different than thefirst communication layer; and identify, based on correlation of theport probing information and the port activity information, across-layer link connecting the first port and the second port.
 2. Theapparatus of claim 1, wherein: the first network element comprises apacket network element and second network element comprises an opticalnetwork element; or the first network element comprises an opticalnetwork element and the second network element comprises a packetnetwork element.
 3. The apparatus of claim 1, wherein the port probingis configured to generate a detectable response at the second port ofthe second network element.
 4. The apparatus of claim 1, wherein theport probing comprises at least one of active probing, passive probingbased on traffic migration, or passive probing based on trafficinjection.
 5. The apparatus of claim 1, wherein the port probingcomprises at least one of: active probing based on a port modulationpattern configured to modulate a port characteristic of the first port;passive probing based on a traffic migration pattern configured tocontrol migration of traffic between the first port and at least oneother port of the first network element; or passive probing based on atraffic injection pattern configured to control injection of traffic atthe first communication layer such that the traffic egresses the firstnetwork element at the first port.
 6. The apparatus of claim 1, whereinthe port probing information comprises at least one of: a port probinginstruction provided toward an element management system associated withthe first network element; or an acknowledgment message, from an elementmanagement system associated with the first network element, responsiveto a port probing instruction provided to the element management system.7. The apparatus of claim 1, wherein the port activity informationcomprises: a message from an element management system associated withthe second network element; or traffic activity information associatedwith the second port of the second network element.
 8. The apparatus ofclaim 1, wherein to correlate the port probing information and the portactivity information, the processor is configured to: correlate timinginformation of the port probing information with timing information ofthe port activity information.
 9. The apparatus of claim 1, wherein theprocessor is configured to: initiate, contemporaneously with initiationof the port probing for the first port of the first network element, asecond port probing for a second port of the first network element;wherein a first port modulation pattern associated with the port probingand a second port modulation pattern associated with the second portprobing are determined based on coding.
 10. An apparatus, comprising: afirst network element configured for communication at a firstcommunication layer and comprising a first port and a second networkelement configured for communication at a second communication layerdifferent than the first communication layer and comprising a secondport, wherein the first port and the second port are configured to beconnected via a cross-layer link; the first network element configuredto: receive, from a first element controller associated with the firstnetwork element, probe information indicative of probing to be performedon the first port; and perform probing on the first port based on theprobe information indicative of probing to be performed on the firstport; the second network element configured to: detect a set of eventsassociated with the second port; and send, toward a second elementcontroller associated with the second network element, event informationindicative of the set of events associated with the second port.
 11. Theapparatus of claim 10, wherein: the first network element comprises apacket network element and the second network element comprises anoptical network element; or the first network element comprises anoptical network element and the second network element comprises apacket network element.
 12. An apparatus, comprising: a first networkelement configured for communication at a first communication layer andcomprising a first port and a second network element configured forcommunication at a second communication layer and comprising a secondport, wherein the first port and the second port are configured to beconnected via a cross-layer link; the first network element configuredto: receive, from a first element controller associated with the firstnetwork element, probe information indicative of probing to be performedon the first port, wherein the probe information comprises a set of portmodulation commands associated with a port modulation pattern for thefirst port; and perform probing on the first port based on the probeinformation; and the second network element configured to: detect a setof events associated with the second port; and send, toward a secondelement controller associated with the second network element, eventinformation indicative of the set of events associated with the secondport, wherein the event information comprises a set of notifications forthe second port.
 13. The apparatus of claim 12, wherein the set of portmodulation commands is configured to modulate a characteristic of thefirst port.
 14. The apparatus of claim 12, wherein the port modulationpattern comprises a set of predetermined signal power level changesbased on a set of discrete signal power levels and predetermined timinginformation indicative of timing of the predetermined signal power levelchanges.
 15. The apparatus of claim 12, wherein the first networkelement is configured to: send, toward the first element controller, aset of acknowledgement responses indicative of execution of the portmodulation commands at the first network element and indicative ofrespective times at which the port modulation commands were executed atthe first network element.
 16. An apparatus, comprising: a first networkelement configured for communication at a first communication layer andcomprising a first port and a second network element configured forcommunication at a second communication layer and comprising a secondport, wherein the first port and the second port are configured to beconnected via a cross-layer link; the first network element configuredto: receive, from a first element controller associated with the firstnetwork element, probe information indicative of probing to be performedon the first port, wherein the probe information comprises a set oftraffic migration commands associated with a traffic migration patternfor the first port; and perform probing on the first port based on theprobe information; and the second network element configured to: detecta set of events associated with the second port; and send, toward asecond element controller associated with the second network element,event information indicative of the set of events associated with thesecond port, wherein the event information comprises a set of porttraffic activity notifications for the second port.
 17. The apparatus ofclaim 16, wherein the first network element is configured to: send,toward the first element controller, a set of acknowledgement responsesindicative of execution of the traffic migration commands at the firstnetwork element and indicative of respective times at which the trafficmigration commands were executed at the first network element.
 18. Anapparatus, comprising: a first network element configured forcommunication at a first communication layer and comprising a first portand a second network element configured for communication at a secondcommunication layer and comprising a second port, wherein the first portand the second port are configured to be connected via a cross-layerlink; the first network element configured to: receive, from a firstelement controller associated with the first network element, probeinformation indicative of probing to be performed on the first port; andperform probing on the first port based on the probe information; andthe second network element configured to: determine a relationshipbetween power received over the cross-layer link and an amount oftraffic on the cross-layer link; and send, toward a second elementcontroller associated with the second network element or a networkcontroller, an indication of the relationship between the power receivedover the cross-layer link and the amount of traffic on the cross-layerlink.
 19. An apparatus, comprising: a processor and a memorycommunicatively connected to the processor, the processor configured to:identify a set of ports comprising a set of ports of a packet networkelement and a set of ports of an optical network element, each of theports having a respective connection type associated therewith; classifythe ports, based on the respective connection types of the ports, todetermine thereby a set of compatible ports, the set of compatible portscomprising at least one of the ports of the packet network element andat least one of the ports of the optical network element; and performport isolation processing for the set of compatible ports, based on therespective connection types of the compatible ports, to identify amatching port pair including one of the ports of the packet networkelement and one of the ports of the optical network element that areconnected via a cross-layer link.
 20. The apparatus of claim 19,wherein, for each of the ports, the associated connection type is anelectrical connection type or an optical connection type.
 21. Theapparatus of claim 19, wherein, based on a determination that theconnection types of the compatible ports are electrical connections,port isolation processing is performed using at least one of portisolation based on port identification or port isolation based on portprobing.
 22. The apparatus of claim 21, wherein port isolation based onport probing comprises at least one of active probing, passive probingbased on traffic migration, or passive probing based on trafficinjection.
 23. The apparatus of claim 19, wherein, based on adetermination that the connection types of the compatible ports areoptical connections, port isolation processing is performed using portprobing.
 24. The apparatus of claim 23, wherein the port probingcomprises at least one of active probing, passive probing based ontraffic migration, or passive probing based on traffic injection.